I have fights booked coming up (LHR-DOH-HKG, HKG-DOH-LHR), all on QR except LHR-DOH which is on BA. Paid cash via the Qatar site for buiness class.

IIRC I did add my BA FF during booking, and this applied fine. However, I then upgraded HKG-DOH to First with Avios - which caused my QR FF to appear across the booking. Faffed a lot with OW MMB pages to try and delete to no avail.

Called up QR today and asked to ensure all flights credit to BA and remove QR FF if possible. Was transferred to someone in the 'Frequent Flyer' department who very quickly said 'ok I have deleted your QRPC number and your flights will credit to BA'. Asked him a few clarifying questions to make double sure, checked the BAEC numbers for both me and my companion, and all seems fine.

Will see where the flights credit! Keeping plenty of recieipts to aid in potential claims later, and will also double check with staff during the actual trip.