CAO48 is the only limiting factor apart from company policy.
You will need to either advise or at least seek approval from your employer, as they "own" your 900 hours a year (assuming you are fulltime employed).
If that's the case, you'll need to ensure any private flying you conduct does not put you in contravention of CAO48 and prevent you from carrying out your "paid" duties.
That's the general situation. Unless you work for QF mainline, it's pretty difficult to do any outside flying and still remain within CAO48.