Thanks for the comments gents.
Have done another re-process to temper down my saturation levels and also reduce some of the colour noise which was coming from the blue channel in particular which must be inherent in this DSLR.
https://www.flickr.com/photos/johnka...blic/lightbox/
Reasonably happy considering it's a 10 y.o DSLR and only 2 hours and 15 minutes of exposure.
Clear skies,
John K.