If I remember correctly, you last posted here about having done an MPL and then achieved an ATPL out of it, and you wanted to convert that to a CASA ATPL. Well, how did that go? Were you able to get the CASA ATPL?
If you trained through the MPL system, you would probably be lacking in the minimum command hours that some of the airlines here require. Virgin who just recently advertised in May, required candidates to have 500 hours of PIC time in multi-engine aircraft. When Jetstar advertised a few years ago, they also required 250 hours PIC time if I recall correctly. This is just to be able to put an application in to the system with no guarantee of an interview.
As I understand, an MPL only requires you to have about 20 hours PIC time. So even with your 3000 hours on the A320 in the RHS, the lack of PIC time may not even allow you to apply as you don't meet the minimum requirements. And they do state that P1/US (or ICUS as well call it here) does not count towards the PIC time. Welcome to Australia!