Sorry for the delay, but what Flux recommended is your best bet. Definitely look over the RAF CBAT page and do the SDT and fuel calculations in the CBAT APP if possible. That reddit thread is a great resource, but don't feel you have to do everything there. Just do exercises in things you feel you're weak at(for me it was math).
You'll see some people say to prepare as much as possible and others say it's an aptitude test and preparation won't help. There's some truth to both of those. Prepare as much as you can afford to, but not so much so that you stress yourself out and spend less time on other things. Main thing for me was staying calm. The only thing you can do is your best, and stressing won't help anything. Just go in there in do the tests to the best of your ability. It'll be miserable, I had 0 idea how well I was doing and failed quite a bit during the tests, turns out I did pretty well.
Sorry for the excessive text. I may do a little write up as there's a few others out there(mostly from RAF guys) and they were very useful to me.
(Congratulations by the way, Flux. Hopefully we'll cross paths at some point. Best of luck going forward o7)