Thanks for all the comments folks. I really appreciate it. I'll take a closer look at the camera mount and focuser next time to see if I can pinpoint what's happening there.
Doug, thanks so much for reprocessing my image. It's useful to see what others can get out of it. Curious that the colour is different and you've manage to keep away much of that reddish noise. Hmm ... time for more practice me thinks!
Cheers,
Carl