This has been said but I'll repeat it: never link your AW account with your own bank, real name etc. Using your own card requires the card holder name and this will be saved - this is what you do in eSales. The fact you can enter 4 digit off your card means all your personal card-holder details are on the AW database. It is likely it will remain there even if you remove your card.
Just use PaysafeCard: pay with cash at the newsagent, and enter the code into the web page, as easy as pay-as-you-go phone.
There are Visa and Master top up cards which you can keep anonymous but PaySafeCard is by far the easiest to use and organise.
If you use your credit card, the payment to AW is not that anonymous on your statement . The reference they use is 'awork.co.uk'. This, on the WhoIs domain name register is linked to the same address as AdultWork.com in Malta or somewhere like that. You do not need to be Kojak to work it out.
The AshMad affair should tell you everything you need to know. All the "I'm single and don't care" posters who will now pop up, just YAWN. Protect yourself punters.