Very little is strictly required. But there are a few desirables.
I'd look hard at adding a suitable MSc, or even an MPhil, to your BSc [and you "actually" need the BSc, rather than "to all intents and purposes"]. This is certainly the biggest and most useful addition. I notice that you're in Australia, which may mean that you want to update to an honours degree first.
I'd also look at CRM trainer qualification.
Presumably you already have a CPL, if not you should.
Basic health and safety management is a very good idea, whatever is normal locally.
Apart from that, it will really come down to your experience and personal and professional reputation.
G