Just a data point. Found a QF reward that I wanted and in seeking to reduce my AMEX balance to close the card in the coming months tried avios for the first time. Instead of directly burning QFF (fairly equivalent number required on this occasion - 82k QFF vs 77250 avios, though saved about $90 in fees via BA).
Was instant to QR. Then logged in to BA and was able to convert the avios to my BA account. This took about 10 minutes to sync across as the balance would show differing amounts across different parts of the BA website. Once this happened, booked and ticketed without issue. Smooth experience.
Thanks for posting this Must....Fly! I've been looking for a J Award BA LHR-VCE flight for next October. Using QFF points the only flights available are BA flights departing LHR at 1720 and 1905 for 30,000 points + £52 each. After reading your post I logged in to my BA account and they had flights on the same date departing at 1035, 1325 and 1415 for 20,000 Avios + $A91.64 each so much better times than the flights BA released to QFF. I transferred 40,000 from Amex to Qatar and then across to BA - the first time I've done this. I've now booked the 1035 flight for us both and it was 40,000 Avios but only $A2 for both of us, so only $1 each! It definitely showed the $91.64 each when I checked several times earlier.
When I check again now it shows for one passenger: 20,000 Avios + $1.00 AUD
When I click on "More pricing options" now it shows for one passenger:
19,250 Avios + $9.00 AUD
15,000 Avios + $30.00 AUD
13,500 Avios + $56.00 AUD
10,000 Avios + $123.00 AUD
8,000 Avios + $159.00 AUD.
When I first tried to book it I was getting a message that there are not enough Avios points and like you I had to wait until the balance synced across different parts of the BA website. If I had realised I could use say 27,000 Avios for both of us and pay $112 I would have done that and kept more points in Amex but I'm happy I was able to book a better timed flight so we arrive at VCE at 1345 rather than 2030 if I had booked with QFF points.
Looking at my e-ticket it shows the Passenger Service Charge per passenger as: United Kingdom as AUD 41.20 and Air Passenger Duty - United Kingdom as AUD 48.70 for a total of AUD 89.90 so close to the AUD 91.64 I saw earlier today that I thought I would be paying.
Hope this helps others who may want to check the BA website for award flights if they are searching for flights to or from the UK nad don't se emuch on the QFF website.