[Mick The Gwailo]

Yes, I got that same error when trying to
switch to a Direct Debit Payment not long
ago... the system just does NOT recognize
the correct C.Card number where you have
to enter it for the "Security Check" ????

On a minus point with this problem, I wonder how you would get
on if you wanted to CANCEL a continuous C.Card
payment ??? ... would you be able to do so, or
would you need to CANCEL THE CARD itself,
(reporting it lost, maybe ?!?), in order to
STOP the recurring payments being debited FROM your C.Card ???