Flat 1, 11 Onslow Square, London, SW7 3NJ

Flat 1 is a detached house in London (SW7 3NJ). It has a recorded floor area of 100 m² (around 1076 sq ft), construction records dating it to before 1900 and council tax band G. At 100 m² this is the 5th smallest of 9 units on EPC record in the building, where floor areas span 70–111 m². The building's EPC ratings span D to C, with this unit at the bottom. The latest certificate (October 2019) shows a D (score 58), a step below the typical UK home. The rating has held steady at D across 3 certificates since December 2008. Between certificates, lighting went from Very Poor to Good. The recommended improvements would push it to C (score 78).

Across 1995–2021, sale prices on this property compounded at 7.7% per year. Today's modelled estimate of £1,754,000 is 23.7% below the 2021 sale of £2,300,000, a rare downward gap that often correlates with deferred maintenance or unfinished works. On a £-per-square-foot basis, the last sale (£2,137/sq ft) was about 173.3% above the typical sold price in the postcode. Most recent transfer: March 2021 at £2,300,000. That sale was during the post-pandemic price surge, when transactions cleared materially above pre-2020 trend.