bertie,
big thread on the ctc scheme, just do a search. However ctc have changed to the pilapt tests recently so a lot of the earlier posts on the aptitude testing at stage 2 are no longer valid, as they were the compass tests.
When i went through selection there were no old fashoned units as far as i can remember, maths was just time - speed - distance problems, rates of climb / top of descent calcs, ratios, things like that. Brush up on long division as well. Can't compare it to the brittania scheme though, sorry, haven't done that selection process.
The group discussion at stage 2 is just a 40 min exercise where you whittle 3 given topics down to 1, formulate opinions yourself and then as a group discuss and reach a conclusion in the remaining 20 mins. Topics can be about pretty much anything. Just listen to what people have to say , put forward your opinions without being too pushy or acting like a d**k trying to take charge. And finally just enjoy the day, it's n ot as bad as u might think!
wbv