Just bumping this with my latest experience of BA and credit card charges.

As you may be aware, BA recently moved to a percentage based model for CC charges - a flat rate of 1% per ticket up to a maximum of £20. (I think that is the correct figures.)

In January, before the new charges came into force, I booked some car hire with BA for this summer. At the time I paid the required £5 CC charge which was due on either the full payment or just a deposit. The total cost was £417 so £5 is greater than 1%. I have just gone to pay the balance and have been hit with another charge - this time 1% of the remaining balance. Effectively I am paying the charge twice. Now, the figures are not huge, but still... I will contact BA to request a refund of the charge.