I agree the tall aspect ratio is not pleasant looking...FWIW, it's not a crop...this is full frame, as shot, but in 16:9 (wide) mode on the Lumix LX5. Not good for portrait mode!
Before I read the other comments, I thought, "Oh, Neil, this is making me seasick."
So I guess you have your votes on orientation.
:(
On this one, I guess I'd have to see more of the scene.
The curves are what attracted me :) to the thumbnail. But the tilt, well it makes me feel lopsided. Nice form and shapes, angry foreboding sky. Even what looks like a bird gathering in the river distant.
I'm not sure about the tilted horizon Neil, but I do like those curves. I think you have accentuated them very well with the black and white rendition, as the froth at the waters edge adds good contrast. There is a nice dappling visibility in the water which is also given definition by the b & w. Good shot, Michele