To be certain which subspecies it is you should provide a photo of the back of some leaves. The backs of the more common subsp. lasiophylla are hairy, those of subsp. spinosa are not.
There is a record of subsp. spinosa held at the Australian National Herbarium from December 1999 not that far from your site. It might be worthwhile getting them to check out yours, Subsp. lasiophylla is the only subspecies listed in the ACT Plant Census (2017) and there are few records of subsp. spinosa near the ACT. Michael M will know what to do.