That might be a good starting point. TZ Rolex Forum moderator James Dowling is a Londonite and he might have some good ideas. Also, I'm sure if you posted a "Watch Tourism - London?" query over in the TZ Public Forum you might generate some responses over there [if such threads remain permissable over on TZ [it's always tough to keep track of which speach is tolerated and which will be censored and expunged]...

Cheers, Good Hunting and we expect a detailed report [with photos] upon your return!