I also make the cranberry sauce a couple of days before. It's so different to the stuff out a jar that I couldn't not make it. A slug of cointreau in it at the end to finish it off.
Cranberries freeze well too if you're worried about the shops running out
Stuffing - never Paxo! Hate the stuff. Sausagemeat/onion/oatmeal, made ahead and frozen then taken out on Christmas eve morning.
I have sometimes bought one of those M&S ham in acacia honey joints in the little tray for an extra meat. The timeslot after you've taken the turkey out to rest is perfect for it.
Potato croquettes - again these freeze really well.
I have bought the steam in the microwave sprouts from Marks before but my dad wasn't keen and it's him that likes them.
Gravy - M&S. My table is in my kitchen and it gets enough of a faff dishing up veg etc without making gravy.
Xmas pud - bought. If I had time I'd make it but there are some perfectly good ones available.
I buy the mincemeat (have made it in the past but it is a bit time consuming) but I do make the pastry.
I feel kind of lost as I'm not doing it this year :/