1. You can write a cheque with the sum of money from your other account and then cash it in to your new account. Some banks will let your transfer money by you giving them the details of your other account and they will transfer the money from there.
2. Yes, you should get your account number, sort code etc.
3. You don't need to know anything I think, just your personal details. You should take identification of you and your current address with you.. e.g. bills & passport otherwise they will let not let you open an account.
4. Contact the students loan company and tell them you need to change your bank details. But I'm not really sure on this as I'm not a uni student yet.
If you have 'net banking, you can transfer funds online. I think you can do this through phone banking too, but I've never tried (I do everything online). If you have neither of these, do it in branch. It'll probably take a few days to clear, whatever method you use.
You don't need to know anything. You're a sensible sort so I assume you've researched what the bank gives you and read the T&Cs on their website already.
Your UCAS letter doubles as proof of impending student-ship and proof of address. You'll also need ID (e.g. a passport). Also, you may want to check how much money they need you to pay in (it was £100 for Halifax) so you can take enough.
You can change your bank details on the SFD website. Only takes a min. They'll then send you a letter confirming the change of details.