Joh
When I did my master in Australia, one of my exam was right next door to a German exam. The professor was trying to usher in her students and, not knowing I was waiting for the other room to open, was quite surprised when I responded to her ushering attempt (which was in German, although you could tell from her pronunciation she was not a native speaker) in the most perfect, accent free German. π
So yes, there is actually a not so small German community in Down Under - especially around Adelaide.
The reason few know is, that Germans living in Australia are usually well integrated and fluent in English, so they do not rely on that community. for support.