For more than a month, on and off, ba.com shows availability on Cathay Pacific but when you get to payment stage, it says that flight is gone to someone else while you were making the booking! I have called BA and have been told that this is in Cathay's ball court. This does not speak well for the use of BA currency: Avios! When I have challenged the agent, they hung up on me! Any suggestions for getting this attended to by BA?