beer = room temp, is dark, and refered to as bitter and is mainly British
lager= chilled, mainly European - similar to Bud, Coors. Stella is originally from Belguim is good. Kronenburg is good also.
Food won't be a problem, you can get everything from anywhere in the world in London, most of the population will be Tourists. If you're really hungry there is always MacDonalds
If you're coming here in May, the National Kit car Show is held over the public holiday at Stoneleigh, about 2-3 hrs north of London.
There is always Brooklands (Museum-I've not been but been told that its good), or the Race Track which is the Worlds oldest purpose built race track- its not complete. These are at Weybridge (40 mins west of London). it just happens to be near Thames Ditton, home to a certain car factory from which Mr Shelby bought a few cars back in the sixties.
Have a good holiday.
Roger