Found basically in the middle of bushland in suburban Brisbane. To get here requires walking through overrun dirt paths that pretty clearly haven't been visited in a long while.
Yes, BCC is definitely Brisbane City Council.
Call it, no. But I did search for it. Nothing specific came up, but I did learn that "3403 8888" is BCC's normal contact number, and several other 3403 numbers point to specific BCC employees. So I'm thinking 3403 numbers in general probably belong to BCC.