http://www.moneysavingexpert.com/reclaim/bank- charges
This website is incredibly helpful - follow it to the letter and I don't reckon you'll have any problems.
As far as I'm aware the situation hasn't changed much in that you write a letter to the bank, they reply offering you less (or nothing), so you write back kicking off again and they send you a cheque - it seems to be a pretty standard process. They'll fob you off by asking you to prove the charges by providing your bank statements which you can either xhoose to do or ask them to look themselves, which could take a while.
I thought when I got mine back that they'd close my account, but they haven't - i've just chosen to stop using it.
My husband got at least �500 back and I got over �100, all accrued over about 5 years.
Good luck