T, have you spoken to the university that you want to get into? They will probably be able to tell you what you need to do for the course you're interested in. I know you're from o/s, but I'm not sure about the need to sit any tests if you have existing qualifications. Which university are you applying to? Monash have specific advice on their website for o/s students. Minimum entry requirements for non current school leavers/mature age applicants

I'd try the university directly. No sense doing a whole bunch of things you might not need. I'm not sure that every university is the same either.