I had a 21st birthday dinner for forty at The Orange. We got the exclusive use of the first floor with a reasonable minimum spend.
Staff were very pleasant on guests arrival and throughout the evening. They were also flexible with us ordering a fair bit later than anticipated. We didn't have to wait long at all for food, and given that forty people were catered for in one sitting, the quality was very high. The two house bottles of wine were not particularly cheap but they were very good.
There was a great calm but buzzy atmosphere and I would recommend The Orange as a great venue for a sit-down birthday dinner party.