I am looking to book some hi value flights in F as a special trip for me and my lady. I want to use my BA Amex Premium Plus card ( to maximise avios) but the total cost is a few hundred pounds above my limit.

I assume is not a good idea to split the booking into 2 and buy 1 ticket pay the balance off and then buy the 2nd ticket a few days later. Is there any option with BA to book both tickets together and pay most of the cost now and the reminder in 3 or 4 days when the card balance is paid off ?

If this is not possible am I able to use multiple cards, say pay 90% with my BAPP and the remainder on my Platinum card ?

Thanks on advance