Word of warning
If you are going to London
STAY AWAY FROM KINGSCROSS
Unless of course you like being proposistioned by men.
But seriously There are plenty of places just off Oxford street that sell really good food. Do not however hungery you are buy something to eat off a street vendor unless you like sitting on the loo all next day.
If you are into Burgers make a special trip to piccadily circus and visit planet hollywood they serve great food there, or they did the last time I was in the big smoke.
One final thing keep your wallet somewhere safe and never get it out in the street as I have heard that streetcrime is abbundent in London now.