Mine's coming on Sunday, I will cook/prepare it on Monday (I push the boat out at Christmas and go mad and buy the veg from Asda rather than Aldi - Aldi's veg tends to 'turn' quickly and they don't deliver).
i buy mine the week before christmas
peel and prepare it all, sprouts, carotts, parsnips, broccolli, or whatever you are having.
then put it in the freezer, on christmas day it can just be put in the pan or roasting dish
same with cocktail sausages and bacon on sticks, make them up, and freeze. also just put in roasting dish.
Saves loads of time on christmas day