That's the place. Actually technically it could be out of the gorge, but it's on the Apsley River between the waterhole and the top end of the gorge, so close enough.
Not Dixon. But you're right that we're looking at a lake and on/close to a reasonably well-documented off-track route. There was a very cryptic clue in my last post.
"Mit der Dummheit kämpfen Götter selbst vergebens."