Applying from outside home country

If you can return to Australia, you are suggested to go back to your home country for application. It is much easier to get it in Australia.
In Europe, you can also try to apply, but it is not assured, because it is unclear that which country you will be then. Some countries only allow those who have local residents to apply in their countries. Therefore, you can wait to consult the embassy at the time you need to apply.