Hi Lisa - this is a difficult one. It is possibly a Southern Tigertail, which are relatively common through the higher parts of the ACT, and down through the Victorian GDR, and there is one record from Monga. But it might also be a Mountain Tigertail, which are generally found in the Blue Mountains area but a few have been found as far south as Gippsland. Your location is somewhere in between. To be confident of an ID, you really need a photo of the lower side of the thorax or a clear shot of the labium (mouthparts) - unfortunately not visible in these photos. I've created a Eusynthemis sp. (genus) category so this one can be accepted.
Thank you for your efforts, and explaining. Unfortunately I only had one quick shot at this beauty. However, I now have a better idea of what you need for ID, and appreciate you sharing your knowledge.