Agrostis are very hard to ID without specimens (need to know whether a palea is present or not, length of spikelet and often anthers to the nearest 0.1mm, etc). I'd suggest you send dried pressed samples to the NSW or ACT herbarium for positive ID (depending on where you are based). Make sure you dig the sample up, as presence of rhizomes is important. You can find requirements for submission and submission forms online
Sorry arjay. I meant to respond to you earlier. Thanks for the extra photo, but as Grassman said, this one will need to be keyed out from a physical specimen. I appreciate you taking the time to take the close up.
A lot of them are flowering at the moment (or have been) so I might put some up ... particularly if it gets any wetter and gloomier. Which it is actually supposed to. And I will be stuck inside.