I started a thread a week ago about burning in complicated skies and got some great advice regarding different approaches.
I left things a while so things might sink in and revisited this shot yesterday using split filtering as well as going about the whole thing from a different angle. I took an exposure time that made the sky look nice and dodged the rocks and foreground accordingly, which seems to have worked far better than burning in the sky.
I still need to split sepia and selenium tone this before its finished but I have run out of sepia toner for the time being and the toning doesn't make much difference to the reason I am posting this here anyway.
Thanks again to all those who helped me improve this print.