My SIL and I are going to London for a couple of nights. We've got tickets for to Kill A Mockingbird but what else should we do. She's never done any of the galleries or museums, I've done some of them but not for years. If you had 48hrs in London what would you do?! I'm sure I read in a thread about a hidden 1940's bar somewhere but I can't find it now. Something quirky like that would be great as we're not overly keen on the standard touristy stuff. Please give me your recommendations for a great London experience