Brook Green agent Justin Knight, of Bective Leslie Marsh, took part in the RICS survey. He said: "Flats under £500,000 are selling steadily now, as are houses and cottages from £700,000 to £1,300,000. Houses from £1,400,000 to £3,000,000 are almost impossible to sell. We expect at least another five to 10 per cent to come off in W14 and W6. Properties over £3million are relatively unaffected."