Finding extended homes…
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Homes within 1 km whose energy certificates show the floor area growing: extensions, loft and garage conversions. Tap a home on the map or in the list for its full history. Back to W1K 3NJ
Not every extension shows here. We only see building work when a new energy certificate is lodged, which happens when a home is sold, let or newly built. A loft or extension added since then won't appear, even with planning permission and building control sign-off, because those records aren't published as open data outside London. Missing work doesn't mean missing paperwork.
| Home | Before | After | Added | Recorded |
|---|---|---|---|---|
| Mayfair Apartments, 9, Charles Street223 m away | 914 m² | 1,321 m² | +407 m² +45% | 2012 |
| 25, St Anselms Place361 m away | 185 m² | 446 m² | +261 m² +141% | 2025 |
| 43, Reeves Mews297 m away | 372 m² | 617 m² | +245 m² +66% | 2013 |
| Apartment 2.4, 1, Grosvenor Square190 m away | 323 m² | 506 m² | +183 m² +57% | 2024 |
| Greybrook House, 28, Brook Street401 m away | 238 m² | 410 m² | +172 m² +72% | 2017 |
| 31, Culross Street485 m away | 222 m² | 366 m² | +144 m² +65% | 2024 |
| Flat 23, Hereford House, North Row673 m away | 200 m² | 335 m² | +135 m² +68% | 2025 |
| 62, Wimpole Street975 m away | 129 m² | 256 m² | +127 m² +98% | 2019 |
| 22, Farm Street |
From energy performance certificates (MHCLG): a later certificate shows at least 15 m² and 15% more floor area than an earlier one (and no more than 2.5 times, to leave out typing errors). Some changes come from a more careful measurement rather than building work. Addresses: HM Land Registry. Contains HM Land Registry data © Crown copyright and database right 2026, OGL v3.0.
| 409 m² |
| 535 m² |
| +126 m² +31% |
| 2023 |
| Flat 14, Glendore House, 30, Clarges Street392 m away | 182 m² | 295 m² | +113 m² +62% | 2019 |
|---|
| 11, Mount Row68 m away | 78 m² | 191 m² | +113 m² +145% | 2014 |
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| 2, Dunraven Street605 m away | 83 m² | 192 m² | +109 m² +131% | 2022 |
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| 22 - 23, Hertford Street514 m away | 106 m² | 214 m² | +108 m² +102% | 2022 |
|---|
| Flat 3, 4, Mount Street84 m away | 93 m² | 198 m² | +105 m² +113% | 2011 |
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| 48, Grosvenor Square146 m away | 194 m² | 298 m² | +104 m² +54% | 2024 |
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| 38, Upper Grosvenor Street370 m away | 164 m² | 266 m² | +102 m² +62% | 2009 |
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| Flat 7, 46, Upper Grosvenor Street303 m away | 61 m² | 149 m² | +88 m² +144% | 2024 |
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| 47, Albemarle Street544 m away | 92 m² | 178 m² | +86 m² +93% | 2018 |
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| 21a, Brick Street497 m away | 61 m² | 146 m² | +85 m² +139% | 2024 |
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| 29, Shepherd Street439 m away | 60 m² | 145 m² | +85 m² +142% | 2012 |
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| 24, North Audley Street530 m away | 82 m² | 164 m² | +82 m² +100% | 2025 |
|---|
| 5 - 7, Dover Street547 m away | 71 m² | 153 m² | +82 m² +115% | 2017 |
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| Apartment 19/20, 1, Grosvenor Place933 m away | 117 m² | 199 m² | +82 m² +70% | 2009 |
|---|
| Flat L, 3 - 4, Balfour Place257 m away | 100 m² | 180 m² | +80 m² +80% | 2024 |
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| Flat 3, 25, North Audley Street520 m away | 126 m² | 202 m² | +76 m² +60% | 2020 |
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| 39, Hertford Street457 m away | 56 m² | 131 m² | +75 m² +134% | 2009 |
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| Flat 3, 6, Charles Street222 m away | 86 m² | 159 m² | +73 m² +85% | 2025 |
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| 11, South Audley Street258 m away | 318 m² | 391 m² | +73 m² +23% | 2011 |
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| Darley House, 27, Gilbert Street360 m away | 52 m² | 124 m² | +72 m² +138% | 2009 |
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| 5, Balfour Place257 m away | 121 m² | 192 m² | +71 m² +59% | 2020 |
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| Flat 1, 4, Green Street516 m away | 137 m² | 208 m² | +71 m² +52% | 2016 |
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| Flat 3, 6, Upper Brook Street410 m away | 168 m² | 238 m² | +70 m² +42% | 2020 |
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| 9, Mount Row69 m away | 232 m² | 299 m² | +67 m² +29% | 2025 |
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| 6, Grosvenor Crescent Mews986 m away | 303 m² | 370 m² | +67 m² +22% | 2024 |
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| 9, Hanover Street578 m away | 78 m² | 144 m² | +66 m² +85% | 2013 |
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| 1, Dunraven Street590 m away | 115 m² | 179 m² | +64 m² +56% | 2022 |
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| Gefinor House 18b, Charles Street249 m away | 192 m² | 254 m² | +62 m² +32% | 2026 |
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| Flat 50, Orchard Court, Portman Square757 m away | 308 m² | 370 m² | +62 m² +20% | 2026 |
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| 42, Shepherd Street427 m away | 133 m² | 195 m² | +62 m² +47% | 2024 |
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| Flat 5, 24, Mount Row102 m away | 144 m² | 206 m² | +62 m² +43% | 2019 |
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| 7, Hays Mews189 m away | 63 m² | 124 m² | +61 m² +97% | 2026 |
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| Flat 74, 15, Portman Square888 m away | 43 m² | 104 m² | +61 m² +142% | 2022 |
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| 3, Marylebone High Street960 m away | 43 m² | 103 m² | +60 m² +140% | 2020 |
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| 7, Green Street522 m away | 139 m² | 199 m² | +60 m² +43% | 2008 |
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| Flat 11, 47, Grosvenor Square160 m away | 127 m² | 183 m² | +56 m² +44% | 2022 |
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| Flat 4, 37, Curzon Street373 m away | 302 m² | 357 m² | +55 m² +18% | 2012 |
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| Flat 1, Bilton Towers, Great Cumberland Place943 m away | 75 m² | 130 m² | +55 m² +73% | 2012 |
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| Flat 15, Ladbroke Apartments, 3, Welbeck Street700 m away | 236 m² | 289 m² | +53 m² +22% | 2010 |
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| 38, Curzon Street373 m away | 195 m² | 247 m² | +52 m² +27% | 2023 |
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| 5, Market Mews415 m away | 127 m² | 179 m² | +52 m² +41% | 2021 |
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| 16, Stratton Street371 m away | 109 m² | 160 m² | +51 m² +47% | 2009 |
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| 107, Jermyn Street912 m away | 106 m² | 157 m² | +51 m² +48% | 2009 |
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| 59, Green Street500 m away | 160 m² | 209 m² | +49 m² +31% | 2022 |
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| 8, Upper Brook Street410 m away | 215 m² | 264 m² | +49 m² +23% | 2019 |
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| 12, Woodstock Street488 m away | 66 m² | 114 m² | +48 m² +73% | 2021 |
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| 10, Reeves Mews287 m away | 56 m² | 104 m² | +48 m² +86% | 2010 |
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| Flat 4, 3, Stanhope Gate403 m away | 134 m² | 181 m² | +47 m² +35% | 2021 |
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| 51, Beak Street847 m away | 287 m² | 333 m² | +46 m² +16% | 2020 |
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| Flat B, Longford House, 24, Wimpole Street973 m away | 260 m² | 306 m² | +46 m² +18% | 2012 |
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| 16, Rex Place310 m away | 188 m² | 233 m² | +45 m² +24% | 2017 |
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| 2, Great Marlborough Street947 m away | 33 m² | 78 m² | +45 m² +136% | 2014 |
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| 7, Grosvenor Crescent Mews986 m away | 104 m² | 149 m² | +45 m² +43% | 2013 |
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| Flat 10, 24, Great Cumberland Place914 m away | 137 m² | 181 m² | +44 m² +32% | 2010 |
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| 118, Marylebone Lane944 m away | 30 m² | 74 m² | +44 m² +147% | 2009 |
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| Flat 11, 1, Carlos Place46 m away | 140 m² | 183 m² | +43 m² +31% | 2017 |
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| 20, Stanhope Row429 m away | 93 m² | 135 m² | +42 m² +45% | 2023 |
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| Flat 1, 107, Park Street589 m away | 92 m² | 134 m² | +42 m² +46% | 2019 |
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| 11, Grosvenor Crescent Mews986 m away | 256 m² | 298 m² | +42 m² +16% | 2019 |
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| 3, Trebeck Street386 m away | 40 m² | 82 m² | +42 m² +105% | 2012 |
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| Flat D, 7, Charles Street221 m away | 57 m² | 98 m² | +41 m² +72% | 2013 |
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| Flat 3, Bilton Towers, Great Cumberland Place943 m away | 90 m² | 130 m² | +40 m² +44% | 2012 |
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| Mead Court, 52, South Molton Street439 m away | 44 m² | 84 m² | +40 m² +91% | 2009 |
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| 9, New Burlington Place563 m away | 65 m² | 104 m² | +39 m² +60% | 2024 |
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| 56, Curzon Street380 m away | 116 m² | 155 m² | +39 m² +34% | 2015 |
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| 37, South Molton Street477 m away | 31 m² | 70 m² | +39 m² +126% | 2013 |
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| 7, Balfour Place287 m away | 194 m² | 233 m² | +39 m² +20% | 2009 |
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| 87 - 89, Mortimer Street986 m away | 74 m² | 112 m² | +38 m² +51% | 2026 |
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| Flat 9, 16, Upper Brook Street499 m away | 135 m² | 173 m² | +38 m² +28% | 2025 |
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| 14, Wimpole Street858 m away | 66 m² | 104 m² | +38 m² +58% | 2014 |
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| 42 - 43, Curzon Street374 m away | 91 m² | 128 m² | +37 m² +41% | 2025 |
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| Hertford Court, 15, Hertford Street483 m away | 41 m² | 78 m² | +37 m² +90% | 2016 |
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| Flat 9, 110, Mount Street68 m away | 120 m² | 156 m² | +36 m² +30% | 2026 |
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| Flat 7, 8, Dover Street534 m away | 114 m² | 150 m² | +36 m² +32% | 2020 |
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| Apartment 1, 5, Portland Place988 m away | 163 m² | 197 m² | +34 m² +21% | 2023 |
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| Flat 41, Berkeley House, 15, Hay Hill369 m away | 68 m² | 102 m² | +34 m² +50% | 2012 |
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| Flat 3, 56, Seymour Street979 m away | 62 m² | 96 m² | +34 m² +55% | 2012 |
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| 20, Dukes Mews747 m away | 109 m² | 143 m² | +34 m² +31% | 2009 |
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| 12, Argyll Street786 m away | 49 m² | 83 m² | +34 m² +69% | 2008 |
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| Flat 10, Welbeck House, 62, Welbeck Street753 m away | 201 m² | 234 m² | +33 m² +16% | 2019 |
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| Flat 1, 37, Green Street615 m away | 179 m² | 212 m² | +33 m² +18% | 2011 |
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| 30, Grosvenor Crescent Mews957 m away | 204 m² | 236 m² | +32 m² +16% | 2025 |
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| Flat 33, Chesterfield House, Chesterfield Gardens336 m away | 71 m² | 103 m² | +32 m² +45% | 2023 |
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| 11, Bentinck Mews859 m away | 83 m² | 115 m² | +32 m² +39% | 2021 |
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| 31, Shepherd Street439 m away | 111 m² | 142 m² | +31 m² +28% | 2014 |
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| 27, St James'S Street750 m away | 106 m² | 137 m² | +31 m² +29% | 2009 |
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| Flat 10, Glendore House, 30, Clarges Street392 m away | 134 m² | 164 m² | +30 m² +22% | 2022 |
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| Flat 61, Chesterfield House, Chesterfield Gardens336 m away | 122 m² | 152 m² | +30 m² +25% | 2021 |
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| 3, Green Street511 m away | 94 m² | 122 m² | +28 m² +30% | 2009 |
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| 23, Harley Place968 m away | 171 m² | 198 m² | +27 m² +16% | 2026 |
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| 36, Bourdon Street316 m away | 114 m² | 141 m² | +27 m² +24% | 2025 |
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| Flat 1, 118, Mount Street0 m away | 67 m² | 94 m² | +27 m² +40% | 2022 |
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| Flat 32, Fountain House, Park Street391 m away | 171 m² | 198 m² | +27 m² +16% | 2018 |
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| 6, Charles Street222 m away | 78 m² | 105 m² | +27 m² +35% | 2013 |
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| Flat 1, 6, Spanish Place893 m away | 50 m² | 76 m² | +26 m² +52% | 2025 |
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| 11, Ramillies Place825 m away | 110 m² | 136 m² | +26 m² +24% | 2022 |
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| 42, South Audley Street209 m away | 123 m² | 148 m² | +25 m² +20% | 2022 |
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| Flat 2, 4, Audley Square301 m away | 114 m² | 139 m² | +25 m² +22% | 2011 |
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| Flat 94, 15, Portman Square888 m away | 108 m² | 133 m² | +25 m² +23% | 2011 |
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| 36, Hertford Street463 m away | 50 m² | 75 m² | +25 m² +50% | 2009 |
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| Flat 11, 17, Clarges Street395 m away | 68 m² | 92 m² | +24 m² +35% | 2025 |
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| Flat 7, 89, Piccadilly502 m away | 43 m² | 67 m² | +24 m² +56% | 2021 |
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| 17, Knightsbridge933 m away | 118 m² | 142 m² | +24 m² +20% | 2021 |
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| 6, Arlington Street638 m away | 72 m² | 96 m² | +24 m² +33% | 2013 |
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| Calder House, 1, Dover Street565 m away | 134 m² | 158 m² | +24 m² +18% | 2012 |
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| Flat 64, Cumberland Court, Great Cumberland Place882 m away | 60 m² | 83 m² | +23 m² +38% | 2026 |
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| B2, Albany666 m away | 98 m² | 121 m² | +23 m² +23% | 2021 |
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| Flat 4, Duke Street Mansions, 70, Duke Street459 m away | 132 m² | 155 m² | +23 m² +17% | 2019 |
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| 9, Upper Berkeley Street966 m away | 82 m² | 105 m² | +23 m² +28% | 2013 |
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| Stalbridge Flats, Lumley Street461 m away | 46 m² | 69 m² | +23 m² +50% | 2011 |
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| Flat 11, 23, Down Street554 m away | 69 m² | 91 m² | +22 m² +32% | 2021 |
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| 16, New Quebec Street920 m away | 112 m² | 134 m² | +22 m² +20% | 2010 |
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| Flat 25, Sandringham Court, Dufours Place900 m away | 51 m² | 72 m² | +21 m² +41% | 2026 |
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| Apartment 2, 2, Curzon Square460 m away | 66 m² | 87 m² | +21 m² +32% | 2022 |
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| Flat 3, 21, Seymour Street863 m away | 57 m² | 78 m² | +21 m² +37% | 2021 |
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| 1, St James'S Street889 m away | 101 m² | 122 m² | +21 m² +21% | 2010 |
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| Flat 24, The Phoenix, 8, Bird Street561 m away | 33 m² | 53 m² | +20 m² +61% | 2021 |
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| Flat 25, Harmont House, 20, Harley Street920 m away | 82 m² | 102 m² | +20 m² +24% | 2013 |
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| 56, Grosvenor Hill276 m away | 116 m² | 136 m² | +20 m² +17% | 2011 |
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| 29, Golden Square773 m away | 90 m² | 110 m² | +20 m² +22% | 2011 |
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| Flat 5a, 2, Mandeville Place714 m away | 99 m² | 118 m² | +19 m² +19% | 2024 |
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| Flat 5, 33, Dover Street405 m away | 88 m² | 107 m² | +19 m² +22% | 2020 |
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| Flat 11, Erida House, 37, Clarges Street425 m away | 45 m² | 64 m² | +19 m² +42% | 2018 |
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| 14, Albemarle Street484 m away | 83 m² | 102 m² | +19 m² +23% | 2016 |
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| Flat 5, Ladbroke Apartments, 3, Welbeck Street700 m away | 43 m² | 62 m² | +19 m² +44% | 2016 |
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| Flat 18, Grosvenor Hill Court, 15, Bourdon Street203 m away | 114 m² | 133 m² | +19 m² +17% | 2011 |
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| Flat 28, Haselbury House, 81, George Street979 m away | 122 m² | 141 m² | +19 m² +16% | 2010 |
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| 12b, Berkeley Mews864 m away | 80 m² | 99 m² | +19 m² +24% | 2009 |
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| Flat 2, 58, Maddox Street437 m away | 73 m² | 91 m² | +18 m² +25% | 2022 |
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| Flat 7, The Phoenix, 8, Bird Street561 m away | 53 m² | 71 m² | +18 m² +34% | 2022 |
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| Flat 1, 37, Bruton Place229 m away | 34 m² | 52 m² | +18 m² +53% | 2021 |
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| Flat 54, Cumberland Court, Great Cumberland Place882 m away | 84 m² | 102 m² | +18 m² +21% | 2021 |
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| Flat 3, 17, Berkeley Street383 m away | 89 m² | 107 m² | +18 m² +20% | 2020 |
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| 12, Clarges Street395 m away | 58 m² | 76 m² | +18 m² +31% | 2015 |
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| Mayfayre House, 22 - 28, Shepherd Street411 m away | 42 m² | 60 m² | +18 m² +43% | 2011 |
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| 96, Park Street495 m away | 73 m² | 91 m² | +18 m² +25% | 2010 |
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| 25, Gilbert Street345 m away | 119 m² | 137 m² | +18 m² +15% | 2009 |
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| Flat 16, Milford House, 7, Queen Anne Street950 m away | 91 m² | 108 m² | +17 m² +19% | 2023 |
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| Flat 4, 11, Bentinck Street828 m away | 101 m² | 118 m² | +17 m² +17% | 2022 |
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| Flat 108, Carrington House, Hertford Street442 m away | 54 m² | 71 m² | +17 m² +31% | 2020 |
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| 8, Queen Anne Street967 m away | 85 m² | 102 m² | +17 m² +20% | 2013 |
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| Flat J, 59, Davies Street365 m away | 98 m² | 115 m² | +17 m² +17% | 2009 |
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| Apartment 9, 1, Curzon Square440 m away | 83 m² | 99 m² | +16 m² +19% | 2022 |
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| Flat 8, 50, Brooks Mews331 m away | 52 m² | 68 m² | +16 m² +31% | 2021 |
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| Flat 5.1, 11 - 13, Pollen Street576 m away | 86 m² | 102 m² | +16 m² +19% | 2019 |
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| Flat 7, Shepherds House, 20, Lees Place497 m away | 38 m² | 53 m² | +15 m² +39% | 2019 |
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| 11, Curzon Street351 m away | 83 m² | 98 m² | +15 m² +18% | 2017 |
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| Flat 22, Hinde House, 11, Hinde Street824 m away | 68 m² | 83 m² | +15 m² +22% | 2017 |
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| Chesham Flats, Brown Hart Gardens386 m away | 58 m² | 73 m² | +15 m² +26% | 2015 |
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| Flat 602, Carrington House, Hertford Street442 m away | 71 m² | 86 m² | +15 m² +21% | 2011 |
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