Well, then, 40 discount economy BA short hauls a year would certainly get you the priority check in, and then the equivalent of £100 a year for Qantas Club membership would get you lounge access on top. It's how I did it for years - and how I was resigned to doing it forever - until I suddenly found myself popping over into the next tier one year.
It may not make sense for your travel patterns, but it certainly did for me as BA/QF covers almost everything that I want to do.