Yup, some good shots here Simon. I'm afraid I'm going to go the whole hog and say the ears cut in half in number 2 ruins the shot for me which is a shame because the rest of it is an excellent portrait. I like the golden light in number one, just one slight annoyance is the blurred twig/branch whatever right by the mouth. Other than it's lovely. There is something about number three that looks wrong, the horse seems all out of proportion. I think it's because of the angle of the head and neck which forms a straight line to the shoulder and takes away any shape.
I love the idea of the horse's hooves in the last pic. Even with the cropped hoof, this one still works and captures something a bit different. Well done
Rob