Thanks Mike - the CLS filter puts a very strong blue cast to the image so I've paid a bit more attention to treating the core of the galaxy as white. It still doesn't have the reddish cast to the centre many images I've seen show, but I suspect that's a limitation of the DSLR's filter.
I also had a bit of a fiddle with the erosion tool in PixInsight to try and sharpen up the stars a bit, but I'm not convinced its much of an improvement.
I'm now having a chat with the guys at astrobin who are a bit mystified as to why my images aren't appearing.
If it does appear, it will be at:
http://www.astrobin.com/20303/
cheers,
Andrew.