When taking pictures I thought this was another T. arenaria so I just took a couple of snaps, but looking at them closely it may actually be something else? Could be T. alpina? The Thelymitras are overwhelming this year..
I'm thinking along the lines of T nuda here. T alpina should be more in the mountains, and apparently has a narrow labellum which this doesn't appear to be the case here. Apparently nuda has a more slender leaf and arenaria a large fleshy ribbed leaf, do you have leaf photos? Agree the Thelymitra are overwhelming!
Looking at this again, the post-anther lobe looks too notched and flattened to be nuda. Doesn't seem to two forward point spurs on the distal part of the post-anther lobe, which would indicate alpina, so perhaps arenaria best guess here