Hi Clive,
Ancient - Made them to last in those days didn't they
The inclusion of the gravel helps as it adds contrast, without it the image looks a bit washed out.
Urban - Not one of your best shots Clive, over exposed and on the skew.
Pair - Good take on the theme. Slight crit that the shot may be a bit front focused, the grass in the foreground seems sharper than the texture of the stone.
Big - Yup, that's a big bridge. Nicely exposed in the bright sunlight. I may have cropped in a little on the left as there is an interloper in the shot which doesn't add anything.