No - I don't think it's C. decumbens, as its anthers are more exserted from the flower (e.g. see https://www.anbg.gov.au/photo/apii/id/dig/50589). At that location it would definitely be either planted or self sown from a cultivated plant.
Certainly not Lepidosperma laterale as given by Carbon AI. A cord rush (family Restionaceae), possibly Eurychorda complanata: culms are possibly flattened (second photo) and leaf sheath appears to be consistent with that species but image not quite clear enough. Unable to enter an ID at family level (ie as Restionaceae). Hopefully someone with familiarity with Restionaceae can confirm or correct.
A more upright form of Correa decumbens? Spreading nature, oblong to narrow elliptical leaves and narrow cylindrical, pink to red flowers with green lobes. An escapee or planted?
Ciaran, we have three Senecio sightings for Top Hut TSR on NatureMapr. There is this one, and also Sightings 4662083 and 4683502. One is unresolved, and the other is S. quad. Would you possibly have the time to check them out and let us know if we have three different species there please?
BTW, Sighting 4621023 just caught my eye, and it is B. glauca. Top Hut is pretty much the only place I have seen it growing in grassy patches.