Finding the species in an obviously urban situation raises the strong possibility that the species has been inadvertently introduced. Finding multiple specimens in different areas on the property where it has not previously been seen strengthens that possibility. It may take years before introduced species become "obvious" in this way.
From memory, so far you have found it at the locality near the Canberra hospital, and now the urban location. It it was a remnant population, I would have expected that you would have found it much earlier in the urban location, and also in other "undeveloped" areas in the district.