Hey Paddy, I have the CASI 2 cert for a few years now. I have actually been training for CASI 3, which I might attempt next season. Firstly, good luck with your exam. Listen carefully over the first couple of days and try to get as much feedback on your riding as possible. At this point really focus on fixing your technique in the areas required.
Do you have any questions in particular? Have you taken any training for CASI 2? I would be happy to help you if you have anything in particular you are working on.
I spent some time writing articles with another instructor (CASI 3 / trainer) last season in Whistler. The articles written by Paul Morgan (CASI 3) in particular are very good and definitely cover the CASI level 2 material. He writes in some detail and explains it very well.
Check out the Rider Progression articles here:
It's also a good idea to go to the CASI website and watch their standards videos.
In general, things to concentrate on are... early edging, good pressure control (staying loose in the lower joints but strong in the core), anticipating the turns, switch riding, even and equal turns, holding a strong edge while carving (see the Edging article).
Good luck and let us know how it goes!