There's a big factory in Shenzhen that turns out tens of thousands of good quality all-metal dive torches that get resold under a bunch of different names. Resellers can specify certain options, but there are only a couple of basic variations.
IMO, the basic body you want is the one that uses 3 o-rings, a rechargeable single 18650 battery, and a Cree XM-L2 LED. They are usually advertised as 1000 lumens, although DGX rates their version at a more realistic 600. It's really bright, so much so that I'd look for versions with one or two low power settings.
I'm not sure who retails these in Australia. In the US, they've been sold under names like Volador, Brinyte and Nitesun. And of course, the DGX600 lights.