just ask, I'm sure they will have something, if not, then ask them if they have anything that can help you with the studying. I dunno if u already do this but I recommend for maths, considering that you do ext. 1, to buy at least one or two other textbooks, that is separate from the one u use at skool, i find that very helpful b/c there's a wider range of q's. Instead of doing the same q's over and over again, from ur skool txtbk, use the separate ones for revision purposes.
I would recommend for biz studies to buy an excel txtbk and write ur notes from there according to the syllabus. The one I use at school has too much info that is crap and that you don't even need.
So, just for maths, practice but for all the other subjects, I'd say to buy a separate book, from skool one, and write ur notes according to the syllabus. That's what I do (considering the teacher I have for biz studies is not very good)
I understand that ur looking for past papers, but if you don't get any, then just write notes according to the syllabus, they cannot test you on something that is not in the syllabus