@mumofLiam Hello. I kind of agree with frisch24, with some additional notes. Is your work in SG more related to business admin or accounting? You'll have to consider (as early as now) yung plan mong i-nominate na occupation for PR, since you don't want to waste your years of experience overseas; ideally what you nominate for your occupation is directly related to your current experience, and then your next degree will contribute to that same occupation.
If the occupation you wish to nominate for PR is totally unrelated to your current work experience, you'll be starting from scratch (as in hindi maccount yun for skills assessment), so you would need to acquire more points after graduation. Nominating Accounting as occupation will require really high points (not sure if 90 or 95 na sila at the moment); I'm also not sure if MBA has a pathway. You'll have to do more research on your own regarding which occupation best suits your interests.
UC is a public uni while Torrens is a private one, so I don't know how big a difference yung tuition fees nila. Some private uni might cost more than the public uni, so compare that as well. I study at a public uni too, and I feel like they a lot of good industry links and university services (24/7 library, student centre, career fairs). Check if Torrens has similar services or industry links, since they can potentially help to make you more employable after you graduate.
As for location, my friend lived in Adelaide for half a year (she's ComSci graduate), sabi nya mas mura daw living costs in Adelaide than Melbourne (where she's currently based). Canberra is kinda nice naman, I think it's still a developing city but not as crowded as Sydney or Melbourne. Check Indeed or Seek job websites for opportunities at the moment for both cities, and see which one has more options in the occupation you want.