Hi and welcome to cag
Sorry your post got missed yesterday ...... what you need to do is to do is find out the total of the charges that have been levied from your account ...... I found the easiest way was to go through the statements with a highlighter then you need to input your charges into a spread sheet ..... there are a few about that work out the interest for you.
Then you send a letter (not including the 8% s69 interest) to the bank asking for the charges refunded to your bank ..... who will send you back the general 'fob off' letter citing the current OFT case and the waiver granted to the banks by the FOS
Post back with any other questions
Hope that helps
Saint