Actually, your MBNA is English too, wholly separate company from its American cousin(s): MBNA Europe Bank Limited, Stansfield House, Chester Business Park, Wrexham Road, Chester CH4 9QQ.

I think you probably have to pay the "minimum" you signed/agreed to https://wwwa.applyonlinenow.com/UKCC...k?eid=3E39D489 though for credit cards:

If the balance shown on your statement is £25 or less, it will be the total amount of the statement balance; or if the balance shown on your statement is more than £25, it will be whichever is the least of 3% of the statement balance or the total of any Payment Protection Cover charges, interest, handling fees and default charges plus £5, provided that it will always be at least £25.

Since you agreed to that; can't just do only £5 without them agreeing to it also. Some creditors you can do that with but not where you have a legal agreement with already without their saying it's okay too. They can drag you into court and no solicitor will be able to help much since it's a valid legal document/agreement.