Just back from a great trip to London with my husband and kids (8 & 14). Here's some of the places we ate:
St. John Bread and Wine---fabulous. Great food and service. My top pick.
The Golden Hind - old style chippery. Nice puddings and cool area.
Ye Olde Cheshire Cheese - historic pub with good food. Service very nice as well,
Up Market on Brick Lane (Sun. afternoons) - insanely crowded but lots of booths serving delicious international and British fare.
Borough Market - same as above. Foodie must do. Oysters are tops.
Frontline - Bad scene. Really - don't bother.
Fatoush - very fresh, authentic Middle Eastern in Middle Eastern neighborhood.
Belgo - fun. Good food and beer.