Yes, it was a punt. Looking at options, I’m still not sure. Maybe Ficinia marginata? Used to be classed as genus Isolepsis. I think that’s closest to what I saw. Probably an exotic. I’m happy to just delete it.
The photos should suffice for an ID, but sedges down here are not my expertise. You could try Karen Wilson, she has helped me with sedges & rushes in the past.
Really interesting. Only 1 sighting in NSW on iNat for this species and very few sightings on SCNM - most recent on 5 Jan 2018 from NSWBionetAtlas. It’s obviously underreported. I thought it was a cute little plant worth recording. Obviously others disagree.