
Having worked in catering I understand where they are coming from, but it's only a dozen or so, this time around, and wont be too much of an issue if I tell them on Saturday.
However if you do want to chose now, that's fine by me. I'll keep a list and give it to them on the Thursday or Friday, with amendments on Saturday morning.
Going by the reactions from last year, I'd recommend the chicken

Itchen, I'm assuming you are still veggie?
Choices:
Roast beef, roasties, veg, yorkie, gravy;
Nut & seed roast, roasted new potatoes, veg, yorkie, veggie gravy;
Half roast chicken, roasties, veg, yorkie, gravy;
Stuffed and roasted pork belly, roasties, veg, yorkie, gravy.
Saturday will be buffet and, again going by last year, should be very good
