Great blog post and pictures, Tom.
We went there a few years ago - autumn but it was supposed to be sunny. Ended up being pretty hazy all day and those endless, twisting, single-vehicle wide lanes only had visibility of a couple of metres. So it was quite a nerve-wracking drive first thing in the morning to get to the valley the waterfall's in!
We found the path down into the valley from the ridge eventually. But it is pretty tricky to locate and feels like your about the step off the side of the mountain. We even left it and climbed back up a bit at one point, thinking we'd gone wrong and were on a sheep track by mistake, before coming back down to it. If you do go back, it's a nice walk back down into and along the other side of the valley. Probably great views without the haze too!