Haggis, neeps and tatties! (You can get veggie haggis.) Vat of chilli con carne. Lasagnas. Chunky broth and bread. Curry- homemade or you might be able to get a good deal from a restaurant to order in bulk.
cheese wedding cake is a great idea as you only need to add condiemtns and grapes to make a really impressive display. Fish and chip van barbecue
I suspect if your DP dioes the buffet he will be worrying about it all day. Coudl it be prepared the day before and someone else bring it? Or you two do all the preparable stuff anf have a caterer just bring a few bits which woudln't keep.
sash - dp is v happy to do the food the day before as i was saying that we do the fancy stuff, eg chilli, curry in slow cookers, fancy rice (and do a fancy fish dish on the day), most of them will be deep fried/oven stuff whilst my aunties do sandwiches, etc (anything basic for them to do). Me and Dp will do our own wedding cake with cupcakes too.
Dp had done this before for our engagement do and he got loads of compliments as he is a v good cook.