Was it planted? unfortunately we received a number of seedlings for our National Tree Day mass plantings from GA that were not local or that were hybrids of weeds such as the Bursaria spinosa subsp. spinosa, Bulbine glauca, and A decurrens x A dealbata hybrids. If the tree was planted but no local it might be another example. Sometimes the stake from the protective guard is still present or remnants of big doughnut mulching... if not local and neither E aggregata nor E macarthurii I suggest to mark for removal.
https://canberra.naturemapr.org/users/22862, could this be E. dives? we found a mature E. dives in vicinity of Clancy's track; we should check for fruits and buds. E. dives occurs in Mulligans Flat and I think I saw it also in Goorroo. I think, we excluded E. aggregata on our site visit 15 June with Martin H.