I think that Foliage would be an excellent choice for your birthday lunch especially if you are thinking of a party of 4 or 6. It's a serious restuarant. Very serious in terms of its food, but the atmosphere is on the friendly and informal side of formal and therefore ideal for a birthday meal. I would not feel comfortable in taking say a group of 6 or 8 (which is the maximum) to GR for a birthday, which might get a bit noisy. The other thing I like is the comfort factor. The tables for four are large, but not too large, the chairs and banquettes very, very comfortable. So you can just relax and get into the meal with out any feeling of being cramped. I value that very highly. Book well ahead and ask for a table in the lower room, confirm that you have that table a day or so in advance or by fax. If you are into wine, then you'll know that Foliage has one of the finest lists in the UK. Try the Condrieu, a half bottle is £38 and you will be tasting a little bit of heaven. I love Foliage. I recently recommended it to some extremely discriminating Parisian friends and they loved it too. I preferred to The Square.