Only problem is that you need to apply to extend it 1 month before it expires in order to ensure continuity. CASA then issue it when they get to it. In my experience this can be within a few days of sending in the application. Means that you can actually only get 2 months out of c of v instead of 3 months.
Good thing is though, the guys and girls at CASA are very helpful and an absolute pleasure to deal with.
If you're flying for a CAR 217 company you can combine CIR and CPL flight test with a base check. CASA were not aware of this until our chief pilot told me to point out that part of the regs to them.
Saved me a small fortune.
PM me if you want more info.