Amazon can't afford to be seen shipping units early, so they'll do their usual thing and ship it three days after it actually releases in time for Royal Mail to get delayed by snow and you'll receive it before New Years Day 2015.
I considered going vertical, but after seeing reports that the PS4 is louder when vertical I decided to just stick to my tradition of keeping the console horizontal.
Fact is, Amazon UK have been getting worse and worse for me all year. It's really quite disheartening really, so I don't actually expect to get my PS4 on the 29th. The only possible up-side to that is that if I don't get it on the 29th I'll be sending Amazon sixteen dozen angry e-mails a day.
Amazon will process it on Wednesday at the earliest.