Our initial though was that it was Diuris pardina with no spots (or potentially very faded spots if you look closely). However, we want to make sure it isn't Diuris aequalis. We're back out there tomorrow, so we'll take more photos (sorry for only taking one!).
Found in dry sclerophyll forest dominated by Rytidosperma pallidum, but very close to the ecotone with Box-Gum Woodland. All in very high condition.