This is not the way to see London.

Make sure you book train tickets more than a week in advance to get discount fairs; make sure you have a good map or guide book; make sure you have spare camera batteries; make sure it is the right day for the Changing of the Guards at Buckingham Palace; make sure you buy tickets for the theatre early before either the ticket office closes or the tickets sell out or both, make sure that free events listed for a week are really going to happen everyday; make sure that the train tickets you have are transferable to later times without additional cost.

We didn’t.

So we had a very long, tiring and quite expensive day in London without getting to see or do much. We did see some of the mounted horse guards, the outside of a few landmarks like Buckingham Palace, Trafalgar Square, Westminster Cathedral and Big Ben. We walked across Tower Bridge, caught a tube or two, went to a pub and came home. Covent Gardens were good though with very entertaining buskers, even a very heavily tattooed one from Australia, and the Thai restaurant had nice food but very strange decor - and it didn’t rain.
It is hard work being a tourist especially with the exchange rate so bad for us at present. The information available on the net is not always accurate and without any local knowledge it is quite hard and frustrating getting around.