Thankx for the feedback guys:)
I'm rendering yet another version now with better, more dramatic lighting. I do aggree about the sandy look of the castle texture. Its just a very simple uv mapped stone wall texture (insanely scaled up (or down ( depending on how you look at it )), whice is actually far too small to seen as its true texture. I may make a more custom set of uv maps eventually if I can be bothered. My main issue is still the trees, when they are illuminated obliquely to the camera they look fine (see left of image), but illuminated parrellel to the camera they look flat (see right of image), and they also look flat if they are already in another shadow.
Thanks again
Richard