If you've done any of the London Walks, which do you recommend (or any to skip)? These seem economical and get good reviews. I think my family would really enjoy one or more, but would be interested to hear what you have to say. (Obviously the pub walk isn't an option with 12 and 15 year-olds, and we're not huge Beatles fans.) We're going in April.
I tried doing a search through the forum, but it wasn't very efficient.