I've attended a meal at Zizzi which had at least 30+ guests and they managed to seat us all together in long tables and at short notice which was impressive. Food was alright, I really enjoyed mine but some people complained it was cold. You should probably like your pasta al dente too!
Indian restaurants are usually very good with groups/reasonable drinks prices and I've often walked past that area near the railway bridge and seen lots of big groups although I can't comment as I havent eaten in.
