£3 mil/ 38% knocked off the ask within a week of starting to market this. Still asking 5m for a sub 3k sq ft apartment though...
They have probably missed the window to sell to Chinese off plan, not sure who else would pay almost £2k/ sq ft for an apartment in Hammersmith, albeit it looks like a nice design and fit out.
At about 2800sq ft the direct build costs might be circa £500k, plus maybe £100-200k to nicely fitout and appoint the interior, furnished. The ~20% in social housing costs and ~25% for developer margin and 5-10% for some other costs. That gets you to £1.1m or £1.20m or something like that, add in some reasonable land value and you are talking £1.5-1.75m fair value, or £600-650/sq ft.