Pulled the 8" Newt to bits and a found a few issues. Focuser was not square due to a bracket I had installed for autofocusing, which then impacted on where the secondary was placed etc. Also looked at the imaging train which was way too long. I adjusted that yesterday and headed out to experiment in some "on and off" weather and realised that the shorter imaging train threw out the focus of my OAG, so rather than try to adjust this in the wee small hours I switched to a finder guider. This impacted on guiding I think, or else my polar alignment was too rough as I got quite eggy stars across the image (all in one direction, although stronger on one side - some camera tilt perhaps), but the image I got seemed to my eyes not to be impacted by coma? Adjust the focus of the OAG this afternoon so now I should have everything adjusted and guiding will be perfect right!!!!??? Seems typical that one problem solved (hopefully) reveals another, and another. Anyway, feel like some progress is being made with it. Another Eta Carina 30x 120s Ha subs. Astrobin:
https://www.astrobin.com/full/345400/0/
Also tried to image the Cats Paw but the stars were much worse which as much as guiding my have been problematic it could well have been that collimation had shifted as you mentioned Colin. Appreciate the advice and thoughts on this.