We are leaving for London on Saturday (by 'next Saturday' I take it you mean what I might call 'this Saturday' ie 17th May) so too late. I am always just a little concerned about walking tours - how big a walk will this entail? On the other hand ones with no walking aren't quite right either - we are going to do a tour which ends at the Cabinet War Rooms, but as far as I can tell, it is a bus tour where we only get off the bus at the War Rooms, and they are an extra charge to go to.
Or you might mean 24th May, but by then we will be in Brighton or, ghastly thought, travelling to Cornwall with five of us, including a baby in a carseat, and ALL the luggage we have brought from NZ. I don't see how everything can fit into a Ford Focus. But trains from Brighton to Bodmin Park seem full of changes where I might get lost and find myself in Bath instead.
Sorry, that is rather off the subject. Is this just a one-off walk, it sounds really interesting. I have a book from the library called Secret London by 'distinguished historian' Andrew Duncan which might have some other walks that appeal to us. I realised when I refused to go down one tube station last time (very long escalator wasn't working) that we miss things by not just walking overground more.
(Wouldn't be a very good idea to come to London without seven pound to spare.)