This is the biggest event that we run in the first semester, usually in the last one or two weeks of the semester just before the Christmas break. The last two years we have done this at the Green Man in Harbourne and not really had any issues. They have been able to get them to give us vegan options although iirc there were no halal options. We have previously done it at the Country Girl but they gave us some issues with organisation. As with any other event, feel free to look around at other places which we have done previously (check the 2024 christmas meal channel).
In terms of choosing a date just make sure there isn't any big deadlines due on that day or the day after, and don't do it *too* late ot ensure that people are still in Birmingham so they can attend, and as with the other big events make sure you can do publicity as soon as possible.