Thanks to Rob and MJB for the recommendation of Kingfisher Park. We had a great time there, even though we missed some of the endemics.
We saw the shearwater roost at Swan Lake on Phillip Island which was easy to access and also fantastic for Black Wallabies and plenty of birds. We got sort of told off by the warden for being there after dark (he actually acknowledged that we looked like we knew what we were doing, which is probably an exaggeration. Snakes. The car park is closed at dusk but there's a pull-in close by.
The Powerful Owls might have gone from the Botanical Gardens. There had been no reports since February when we were there. One staff member we spoke to though that the owls might have moved on when the Fruit Bat roost was 'relocated'. We wanted to see the bats so went, as instructed by same staff member, to Centennial Parklands. The roost is close to the Spruce Goose burger van (excellent burgers) and there were lots of birds in the area too, but 4 Buff-banded Rails were the highlight (we couldn't find any in the Botanical Gardens despite quite a search). They were along a stream near the Spruce Goose and the roost. There's a small, cuboid brick building in the trees and close to the stream and they were quite easy to see near this.
We saw penguins at St. Kilda and managed to get back to Melbourne for some comedy shows.