Yes, I'd agree with the previous post. A bit of darkening in the sky should do it. I don't reckon anything else is needed. Maybe we'll bump into each other around Ingleton or its environs some time, I was up with my little lad doing the waterfalls walk (for the umpteenth time) the other day.
Thanks for the comments. I have just done a 10 x 8 work print of this image, the only burning in was about 1.5 stops extra for the sky, the rocks and fore ground printed lovely at grade 2. Just for info I printed on Ilford warmtone using their cooltone developer then gave 3 mins toning with selenium at 1+4. I must say the printed image is significantly better than the scan...wish i could work out someway of scanning and uploading it hmmmmm...