Check out this website. You can claim back bank charges for the last 6 years.
I know it works as my son got a hell of a lot of money back. There's a letter to download and basically all you have to do is fill in the amounts. easy peasy.
In metro this morning it said that they are sneeking in higher rates into the small print and shortening the interest free periods to make the money up. My claim went in the post today, hopefully will get a nice cheque!