Poor photo with phone camera at night, sorry. Possibly Kreffts sugar glider? Distinctive facial markings, small size, hugging the branch. I have never seen one in the Watson Green Space before in very regular night walks; I have seen one in the adjacent Justice Robert Hope Park a couple of months ago, but normally only see them further up on Mount Majura.
Hi Mary, When I download the image and zoom in, I can see at least three things that might be a glider or might be leaves. In short I cant see it. The AI (Carbon) says it can see one. I'm unsure how to interpret that. However I think you know the species from other sightings so I will verify this record, based on your verbal description. The only local species of mid-size grey glider is Petaurus notatus, Krefft's Glider (which we formerly called Sugar Glider).