Originally Posted by
Globaliser
And IME, if I've put in an incorrect CVV for a transaction and the card issuer declines to authorise, it doesn't appear on my account as an authorised transaction that holds part of the credit. That's why I'm wondering whether the OP's actual problem here might have been an Amex glitch and not a BA glitch (notwithstanding the prevailing belief on FT that everything that goes wrong must be BA's fault).
.... which is precisely why I said another bug and did not attribute it to either BA or Amex. It is a bug clearly if an invalid CVV is entered and the funds are pre-authorised. Your assumption seems to be that this is an Amex glitch but I would be surprised if the Amex CVV validation had such a basic bug in it.