As Claire said there is everything!
Italian: go for pasta with a tomato based sauce as this will reduce the syn intake
Chinese: Noddle bars... chow mein is low in syns compared to everything else.
Most places do Jacket Pot's with fillings.... beans will make the whole thing free no matter how big it looks.
Thai: again noodles are available here
Indian: I've not had an indian yet but I guess these would be high syn value whatever you ate. If you go for this have a flexi syn day and just get back on track the day after.
Sandwich places: most do salads which would be better than having bread. If you do have bread though and still have a HexB then you can minus 6 syns from the sandwich total if you have brown bread.
Take your SW book in your handbag and have a sneaky peak whist waiting to order but don't stress if you can't find anything on the menu. Just go whatever you fancy but try and work ou the syns and count.