I have been looking at this some more Ben, I think I would like it better without the tree, or at least having the tree on the left hand side of he frame. I am thinking with that diagonal line angling up through the bottom of the rock below the castle, it's almost like a stairway going up to the castle, but the tree is covering the very bottom entrance onto that "stairway". Also, the left side feels a bit empty compared to the right because of how there is more sky there. So having the tree on the left side would help fill that space.
Did you shoot it from any other angles?