Could be Juncus usitatus or J. subsecundus. Close-up pics of the pith in the culms (continuous or interrupted) and the basal leaf sheaths (their colour) help to confirm IDs of these 'leafless' spp. of Juncus
I might be able to get a sighting this season with pics of the appropriate parts for identification. Basal leaf sheaths shouldnt be too hard. To photograph the pith, does that mean breaking a flower stalk to photograph the pith inside?
Yes, Trevor, use a fingernail or fine knife blade to slit a culm longitudinally - do it at about mid-length of the culm because the pith can vary near the base or top of a culm. See also the notes under the generic description for other features at https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Juncus