yyzflyer, we got two complete separate rooms, very nice, for a very good price inclusive of VAT. We were referred here by a friend and very pleased.

I would suggest spending more time outside of London, but that is just me. I would expect to spend US$700 or more per day, perhaps $500 on the low side, if you want to go to the theatre and sit in decent seats. OTOH, you could go for $200 per day perhaps, staying and eating very low end.

m, you are right, the British Museum is free although there is a suggested donation of 3 pounds. I apologize for missing this detail. Other attractions (Tower, even access to look around the colleges at Cambridge) cost money, often 3 or 4 pounds per adult.