If you can set a forwarding address for your mail to either a family member (if there's someone you can trust)or to the UK, I would strongly suggest doing that because if you *do* forget to cancel something, the spam you get will help remind you! hah
Also, I would suggest maybe not cancelling your US bank account if you think you'll be travelling back a fair amount and making sure you enable online banking if you haven't already because I find it cheaper and easier now to just transfer money from my UK account to my US account when I'm preparing to visit back home (and sometimes, if I'm ordering something from the US to my deliver to my mom's back there - which is what i do with my family's Christmas and bday presents - I need a US bank card so it's handy for that as well). Also, it's useful for student loans or any other type of payments you may need to make in the US while you're abroad.
I'm sure you've got all your bases covered as this isn't your first rodeo! Best of luck with your moving!