There is rarely any point in converting a PPL from one to another, especially if you're only using it as a stepping stone. Likewise but for different reasons it's rarely worth converting a CPL. The CPL requires the most hours of everything except ATP(L) so it's sensible to do that last. If doesn't make sense flying 200 hours to get one CPL only to then fly additional hours to get the other CPL. However, the IR is a different kettle of fish as it can be done and converted well within the CPL minimums.
My advice to save money: take all the financial assistance you can get and complete your PPL, IR, MEP, MEIR etc in Oz. Whatever you can get in the first 180 hours, but don't bother with the CPL. DO make sure you get 50 hours PIC under IFR: you can use the CBIR route to get a very quick CAA IR (training to proficiency) then finish with a short (15 hour) CPL course.