I'd be ready around the time Ferret mentions
It's my first time too. There are plenty of literacy and numerical tests around, you can find this sort of stuff on the web. There is also a course that TAFE offers, specifally around this testing aswell, but i think it runs for about 6 months. My mate did this course and he is now in.
That's interesting around the feedback part. Having interviewed plenty of people in the past in my current line of work, the most i've done is about 15 over two days and it gets a bit hazy remembering that many.
Ferret, was it the interview they didn't pass you on, or did they say anything about the aptitude and profiling as part of the reason? I've heard the feedback isn't great, but if you don't know what the work on.... hmm.