Hi gradient,
I took a 30 sec exposure at f22 with the lens cap on as you suggested.I have put a cropped sample of the image at the link below.This is just a crop..no post work.If the image is enlarged you can see the is a mass of noise in there.
I also tried changing the memory card......just in case but still get the noise.

http://www.landscape-images.co.uk/awful2.htm

I am not sure what I should be looking for in the EXIF files so I put them on the page as well.
Thanks for all the replies.....I have a dreadful feeling I am going to be told it's a camera fault.