Hi Rob. The way the Australia Project prefers that categories be requested is for you to edit the appropriate section of the free-space page
Australian Categories Waiting to be Added or Renamed
It helps to provide the WikiTree ID of a profile that will be in the category.
There's nothing on that page saying it deals with place names. Profile is Peter Cahill
The category Unknown Location, Victoria already exists. Typing Unknown Victoria into the category picker in edit mode on a profile should bring it up.
If you provide a link to a profile that you want the place name category added to, I'll get it done.
As Jim mentioned above, you are welcome to add any requests for new Australian categories to that category request page.