I would like to visit London between 26.12-3.01.05.
I am asking you if and which museums are opened in that period? I really hope that I can visit anything without being afraid that because holiday they’ll be closed.
What about stores? Are they opened?
I also like to visit London’s surrowndings. Are the buses traveling?

A: most London museums and stores are open during that time, apart from on christmas day.

And yes, the buses will be running – even on christmas day, though probably with a reduced service on that day.