I agree that London offers everything for food, It is the probably the world's best melting pot, but there are not any English cookbooks. I am Irish and Irish food is about avoiding starvation and not taste. When in an area ask the locals where they eat. Be prepared for long lines at immigration at LHR when you land. Certainly get out of the city in ANY direction there is a lot of see and do with just random experiences, no planning involved.