I served my mission there and I agree that British food is not very impressive. That said, London is one of the most cosmopolitan cities in the world. You have access to an incredible variety of ethnic foods. If you like Indian food, there aren't many better places outside of India for it. Mediterranean food options are also excellent. I haven't been over there for a few years so I don't know what the current "hip" restaurants are, but you can quickly figure that out online.