Ibram, I've just picked up a London Walks tour guide for 2007/8 which covers the period that you will be in London.
Link here.
When I saw the
Oscar Wilde Walk and the
Beatles Walk I thought of you.
I've been on some London Walks myself, one with my parents who grew up in London. They are pitched at a high enough level of intelligence to be really interesting and the guides are professionals who really know their stuff and can answer questions around the subject as well as random topics that crop up. I've found this company to be the very best.
I intend to go on a walk this Sunday - I can't go to the gym until 13.00 so it will give a meaning to my usually lazy morning. I'll take my camera and report back.