All credit goes to a few different comments over a couple of different posts.
Only steam and EB games (thanks to poster below) offers steam version, however it will launch and require login to rockstar anyway, so I was happy to skip having it in my steam library to save paying ~$75 USD for a game ive already played heaps on PS4.
Use hola to bypass the aussie tax. credit to endee for this suggestion.
Any questions leave a comment and Ill explain further, worked perfect for me and im pre downloading it now.
@dy4me:
Nah, I got my code 5 hours later for other games from Nuuvem.
But the image is just proof that they do have licence keys for GTA5.