Thank you Martin, haze is certainly wip, so cheers for the tips.
I've come to realise that the Lake object isn't quite right on it's own for choppy sea, I've got a few ideas from prevous tries to play with, so think I know what to do there.
The rocks in the cave on the second image I've deliberately exagerated their lateral displacement for a quick render to show proof of concept, they'll be pulled back for the main scene.
Cheers
Jon