Right... Now all is clear, I went to the site of the former Lotus Works in Hornsey yesterday.
Stan Chapman's former Railway Hotel is now an asian (?) restaurant and Funky Brownz bar.
http://www.allinlondon.co.uk/clubs_bars/venue-7075.phpEvidently it did not last long as a pub called The Wishing Well.
The white square that you can just see on the side of the Jewson's building in the Google Street photos is indeed the Colin Chapman memorial plaque.
I took lots of photos and will post them here when I've twiddled their sizes etc.
There is no evidence at all of any plan to convert the site to a Lotus Museum.