Well 200-odd views and not one guess?
Hint: it's a trib off a major North East river, but doesn't seem to appear in any guides (not sure about the Nick Doll one, because my copy has wandered). It would need heavy rain, but probably no more than other more well-known tribs in the area. Its about 3km long, with a bouldery flat bit for the first km, followed by a gorge section before opening up into a valley, with a few drops and slides. I reckon it'd be a technical grade 3 maybe going to 4 for the gorge in high water.
Here's a couple more pics:
Probable put-in (if you could float here the rest would go!):
Start of gorge section ~1km in.
Drop at open bit near bottom:
Come on someone else must have a clue, or maybe even run it?