No not necessarily, however if it goes to Court you need to have your argument in place, there is plenty more reading on the subject here on this web site under various contractural headings. In precis, and how I have gone about it is....
POC from web site amended to any particular issues you have with the CC.
I am claiming
2. Interest the credit card company has charged you on those charges (demonstratable Interest - DI) at their applicable current rates, so you need to look at each statement, as this will change over time and is compounded.
3. either Contractural Compound Interest un/authorised rate (again various thoughts on this) or S69(8%) as an alternative offer for the judge to decide on the POC. you need to give a brief argument for trying to charge them CCI. If you look at my MBNA thread, it's all discussed fairly well there, with some more knowledgeable others.
I currently have one in Court awaiting a defence from CAP one, and MBNA and Capital one are going in next week, Egg are capitulating, but no DI or CCI only offering me 8% so I may take them to court as well.
Hope this all helps,