Well it all got sorted, and I'm typing this at Flight Screening in Tamworth!
Re: aptitude testing ... It turns out that even though Defence Recruiting has been gathering data with the AUSBAT tests for the last ten years or so, they're not actually using it for the selection process after all. It's still the General Aptitude Score that determines what you get offered.
Flight Screening is certainly challenging, lots to learn in a short space of time. Speaking of which, I'm off to study.
P.S. Kiwi knock-knock joke:
Knock-knock
Who's there?
Zachoo
Zachoo who?
Zachoo bro?