okay, so now i've compared the full frame shot with naskies 'sky survey' image, and maybe i was a little hasty to call "amp glow"
here's one example of the red glow i was referring to - with NGC253 as the example. normally i would run DBE hard to get rid of this, so for this example i went back to the unedited stacked image and just applied a stock DBE and histogram stretch only. This was with 4 minute subs in cold weather.