Greg : not directly answering your questions, but I found some names that can be of help while googling.
The London Chess Club played in Parsloe's Coffee House , since 1774 in St James's Street in London. Maximum was 100 (!) members, application money was three guineas. Parsloe's was finally closed in 1825.
There are a dozen names known of chess café's in London (The Divan!), but I didn't find anything more about The London Chess Club; you mention "legends", from what dates is your info on this Club ? 19th century ?
I am visiting London in a few weeks. I have always read about the London Chess Club where many of the Legends of the game were members and played. I googled but found a few websites for clubs but none which looked like the London Chess Club I have often read about. Is there such a London Chess Club in the centre of London? Where is it located?