Did you happen to take any pictures of the labellum from the front? At least two species are known to occur in the area and are distinguishable by the labellum.
Thanks. The second image is definitely umbrinus, and I have confirmed based on that. This sighting has a comparison of the two species if you would like to see the differences: Bunochilus montanus (Montane Leafy Greenhood)
I went back on Friday to look at this site again Matt and there were good numbers of B Montanus flowering, maybe 10 infl. or so. I've come to the conclusion I can't see why they're not Montanus.