We will be spending a couple of weeks in London at Christmastime, living in a house-swap in Hampstead. We're looking for a good Christmas dinner -- a trick since most restaurants are closed. Any thoughts? Also, any local restaurant favorites would be appreciated. We eat all up and down the food scale, from cheap stalls to fine meals any and all ethnicities. We have 4 kids, but they are fairly intrepid diners. Thanks!