You are all doing it wrong!
I honestly don't know why you lot bother. Of course the stock in store on the day will be TOTALLY wrong because everyone without exception has bunged a case of wine in to secure their slot. Tinkering with the order a week before is too late for Tescos supply chain to magic a turkey, pigs in blankets, brussels, etc
My cunning plan is this.
I have already shopped anything extra we might want eg boxes of chocolates or snacks ONLY when on offer , alongside my normal shops carefully checking best before dates are not too long.
On the Wednesday or Thursday the week before the week with Christmas day in, I get up early and do my Christmas shop, with a list, in the supermarket of my choice, before work. This is because most stores restock for the weekend starting on Wednesday. All the veg is peak condition, and quite often the exact same stuff they'll be selling next week! I store it in the darkened shed in the garden if the weather isn't too warm, this year it might be, so out will come our Spare Fridge in the garage. As the veg is peak condition it's still just as fresh 10 days later, and quite often it's 10% cheaper than the following week! Anything I cannot get I may do a massive detour to the farm shop the following week - good quality but a long way out of the way , I do wish it were nearer! Eggs we buy locally (used to have our own hens)
Our Spare Freezer is already in action - frozen peas, beans, onions etc from the garden and a couple of brace of pheasant - thanks Neil) , but I'll add enough milk and bread to tide us over from Christmas to New Year.
I have already ordered my turkey and pigs from our butcher, I'll glide by and pick that up on Christmas Eve or the day before. Best time is about 8.30 in the 'breakfast lull' when there is less queue - I can get it home before I go to work if I'm working.
I do not shop Christmas week or between Christmas & New Year unless we fancy trawling the late shelves half an hour before closing for bargains for the freezer (bought gammon for about 10p/kg last year) M&S and Waitrose are good for this as all the nice posh over-priced fancy stuff they couldn't sell is an absolute bargain below 'normal quality' price, so we treat ourselves.