PSITTACIFORMES: Cacatuidae
Calyptorhynchus lathami
After much research I found that the locals knew that glossy blacks gathered at sunset to drink, feed and roost at a particular spot but it is not publicised.
I went to this spot and waited and suddenly, on time, they started turning up. I counted 20 but may have missed some.
The male is on the left and the female is on the right, The female has a lot more yellow on the side of the face than the male.