Imperial War Museum is well worth a visit, as is the Muesum of London. Natural History and Science museums would also fit.
A key culinary misapprehension to correct. Pubs do NOT serve good fish and chips. For that you need a fish and chip shop, Golden Hind in Marylebone would be my recommendation in addition to being in a great area to explore. The overall eating scene in London is stunningly diverse and comfortably rivals NYC. You will need to be very specific in what you want to try, and budget too, but good Indian food is plentiful if you avoid Brick Lane.