Hi Ken - These are definitely not Common Flatwings. I'm pretty sure they (at least based on photos 1, 3 and 5 in particular) are in fact Alpine Flatwings. I'm completely unfamiliar with the territory to the north of Blues Hut, but Alpine Flatwings are usually in very slow flowing or essentially still, heavily vegetated, boggy wetlands and seepages. They are also noticibly smaller than Common Flatwings. Does this fit your observations.
Thanks Harvey, sorting out the species in Austroargiolestes and Grisargiolestes does nothing but continually confuse me. The habitat was as you describe it! and they were small weak flyers (flimsy fluttering between the sedges), didn't realise they were damselflies at first. I wasn't happy with my suggestion but had a complete brain fade wrt Grisargiolestes. So yes these are Griseargiolestes intermedius.