Did you guys make your bound reference throughout the year, or nearing exam time?
You should be aiming higher than 42 for Further. Don't limit yourself. Trust me, if you learn what you got wrong well from the 2006-2012 VCAA exam papers, you can go from a C to an A+. If you aim higher to start off with->closer you'll be to the A+ to start. Srsly, I'll be close to 42. If I've come close to 42, you should beat it.
Edit: And I made a par-ish bound book for Core, then for Matrices, then for Networks (Networks was just the A+ Further Notes scanned and printed/pasted) and then I started using my girlfriend's old bound book (second to none) and got familiar with that and put the questions I got wrong and explanations on spare pages. It would seriously be worth making a bound book even if you weren't going to take it into the exam lol.