Originally Posted by
luftaom
With hindsight I suspect that I might have been better off swapping to BA - although it would have been a right pain to not be able to use the priority security lines at T5 and then have to wait around at the door of the lounges whilst they see whether you are eligible to enter.
That's what I did. Put your QF number when booking and then switch to the BA number at the lounge service desk. Never had a problem.