Mike I do follow up monitoring all the time preferably 1 or 2 years after tackling parent plants - I monitor treated sites and follow up since over ten years because the seeds survive a long time in the soil seed bank. I found that less and less germinate, however, we can't win since Government cultivate Cootamundra wattles nearby in areas surrounding Mt Majura nature reserve, such as on an offset site block 578 abutting nature reserve to the northeast, see https://canberra.naturemapr.org/sightings/4723338, or along the Fed Highway, or at Epic....
Cootamundra wattle is a declared pest plant so I don't see that the Government is cultivating them; maybe just ignoring them because of lack of resources. I don't worry too much about them in Isaacs/Mugga because there is a lack of other natives.
well perhaps not cultivate, but Gov staff pruned Cootamundra wattles along a road at Epic where they planted some eucalyptus ... I didn't understand why the cootas weren't removed all together when they were still small. It will be more work to prune year after year if the purpose of the pruning is to reduce the branches overhanging / stretching into the road