Shareholder - BA uses their own computer reservations system. I can assure you that Finnair and Iberia share the same CRS , which I think is Amadeus.

I made a booking through my travel agents' computers system, SABRE.

MADRID- BARCELONA on IB, Business Class.
Then, FINNAIR, STOCKHOLM-MANCHESTER, and BA, MANCHESTER-LONDON. Then I asked him to give me each airlines' respective PNR code. I was crediting IB on Qantas, and Finnair and BA to AA. Imagine my shock and horror that BOTH IB and AY had the same identical airline PNR. (It's different from SABRE's locator).

No, no, no, I told him. Book the IB sector seperately and the Finnair and BA ones on another reservation! I cannot chance it that either IB or AY can 'see' each other's reservation and credit all the miles incorrectly.

I did that so that I wouldn't have to pull my hair out. My travel agent however has already pulled his out over my very many different itineraries!

I have an IB flight coming up over the weekend. AMS-BCN on Friday, which I will credit to QF's programme. Then on Sunday, I will call IB up while I am in BCN to ask. them to 'take-out' the QF FF number and replace it with an IB one. Hopefully, they will only be too gladly to do that! Then when I travel on Monday back to AMS, the reservation should only have the IB FF in place.