Don't remind me of one of the greatest bones of contention between me and DP.
For me, Christmas should have a light breakfast around 7-8am with all of the overpriced fruit (and quite possibly pancakes with lemon curd and yoghurt), followed by making sure everything is prepped ready, getting outside and then sticking it on to be done by 2pm so that the rest of the afternoon is spent on the sofa eating and bitching about the TV, leaving enough room for further overpriced fruit, cheese, pickles and salad stuff in the evening.
DP's version is to complain about how full he is from the lasagne he made the night before (which I don't particularly like), complain about the state he left the kitchen in, cook about five meals' worth of fry up and no vegetable matter, leave all of that over the kitchen, then declare it is impossible to think about cooking a dinner and wouldn't it be better to not bother with anything but a chicken thigh and two potatoes because he's got to clean the kitchen up 'in a minute'.
To make this worse, he also mistakenly believes that because a single slightly larger Sunday Dinner needs to be cooked once in late December, this means that no roasted meats or vegetables should be prepared or consumed from November 7th - February 14th.
For the OP to have lunch at 4pm (which will probably turn into 6.30pm), that means breakfast will be had around 10-11am and everybody's going to be starving for hours, IMO.