Hi Jem, looks like your shutter speed was a tad slow, you have what looks
like a double exposure with the outline of the rider and horse. As a rule of
thumb your shutter speed should be at least the focal length, so for example
a 200mm should be over 1/200s to avoid camera shake, if the days is dull
and you find you cant achieve a fast enough shutter speed, then increase the
ISO which will help.
Watch out for cutting off heads and legs, I think you would have achieved a
better composition by including all of the horse and rider, but maybe your lens
didnt allow for that? Just opinions of course and hope it is of some help. :)
Another note, getting the behind of rider and horse won’t do much good.
You are much better positioning yourself front on, or at least side on.
From behind isn’t good.
Your shutter speed and ISO seem fine. No idea why there is ghosting at the top of the image. Maybe it’s a fault with your camera. If it is, you should get it checked.