What can I do when RBS refuse to remove a late payment from credit profile?

Not really, it becomes "overdue" only once they have asked for repayment. If they ask for repayment as part of the statement "minimum payment due" then that is not overdue until after the "payment due date", which is also shown on the statement. Unless they contact me mid-cycle and exercise their right to "request" payment immediately - and I did not pay - then it would also be overdue.

That section is still strangely worded to me. Regardless of whether it is possible to piece all the sections together - I'm not sure how anyone could deny it would just be clearer to say "any interest, default fees, repayment protection insurance, overdue amounts, amounts over your agreed credit limit, and 1/12th of any annual fees..."

Based on the above, if the DD is set up to pay the "minimum payment", then I don't see how Amex is entitled to take to take an overlimit amount at the same time.

Thanks very much for the update. Seems the struggle paid off!

That said, a single late payment marker doesn't make much (if any) difference after a few months. I had one recently (an error by Barclaycard) but didn't bother to have it corrected. My Experian score (for those that believe in them) dipped significantly, but is now 999 again after just a few months.

Ditto a few years ago with Nationwide.