Hi Michael, this looks very different from all other Cotula I've seen, it has a very erect form, not the low, sprawling form of Cotula. The flowers were significantly larger. I have collected a herbarium specimen so I can get an ID from that if necessary.
Yes thanks Natureguy if you could arrange for it to be dropped off at the black Mountain CSIRo herbarium or Bot Gardens - I did key your record out but i did have doubts so will be good to have a recorded confirmed.