[markgozz]

Andy it would be very handy if you could tell us what set up you used to take this shot including any filters .

But for now me critique is :-

Uneven sky exposure ,
Colour cast ,
Lens flare spots ,
Castle has been thrown into too much shadow ,
Odd patches of light and dark areas ,
The composition is going to be down to personal taste but I would of tried a much lower shot to give more interest to the sand ridges .

As I've said the more info you can give on your set up the more help we can give but it looks like you may of picked the wrong time of day to take this shot ( in regard to the position of the sun ) so I think a multiple exposure shot would of worked better or a strong ND grad filter if you haven't the editing software for combining multiple shots .

Mark