Im in the same boat as you mate, however im in a different industry. I have 5 years of experience and tafe qualifications but it only gets you so far. I bit the bullet and enrolled part-time in uni so i can still work plenty to gain experience (and so im not a poor uni student) and still be studying away. At this rate its going to take me around 4-5 years to complete a 3 year course, which sounds like heaps longer, but finishing it around the age of 25 doesnt bother me in the slightest as it will mean i will get more money after i finish than some 21 year old with the same degree, but zero experience.

Definitely have a chat to some uni lecturers/course co-ordinators to find out what you will get exemptions from and what other tips they can offer you. Also try contacting a future prospective employer, to see what types of qualifications/experience they might be after so you have a general sense of what it takes.

Im at curtin and find its a great place, but cant speak for any of the other unis in Perth.

Good luck mate.