The Instructor rating is the same apart from the 30 hours mutual time.
That doesn't seem like the same to me. Perhaps I'm a slow learner or else I had some good fellow students but I learnt a whole lot with my mutual flying.
One significant difference is that the CASA FIR includes spinning but I'm sure that darksarcasm will do that regardless.
GA instructors straight from a CPL get good at it after a few years so I'm sure that the RAA situation is the same.