I can vouch for Clos Maggiore, food is great and a decent atmosphere.

Jamie's Italian on Threadneedle for dinner, while not the best sounding restaurant name, is excellent food and the back room is cosy. Wine list is very solid and the food is of that farm to table/organic / good for you blend.

Frankly, some of the best food I've had in the last few months in London was a tapas place in Islington, a few blocks from the train stop. That whole area is fun to walk at night.