Sports Direct has housing above it and it is built within the bentonite wall. I see no reason why housing is not possible (above ground floor) if a food retailer is possible on the site.

As a retail site it is probably worth less than £10m fully developed, based on the value of eight units to the rear at £13m http://www.cushwakesales.com/Data/CWI343...denham.pdf

If we assume a two bed flat on the site might be worth £300k, it would require 30 of them to be worth £10m. That's less units than planned for the Portacabin site across 3-6 floors. In Bell Green there are already 7 storey buildings, and the footprint is much bigger than the portacabin site.

It would cost much more to build flats on the site than to build a big warehouse. It becomes a matter of how many flats you can sensible get on each floor, how much social housing provision, and how high would be acceptable. At some point the profit from housing would be greater than the profit from under-utilising the site for retail.