Looks like you've got some joyously good data there.
I feel that it's over-processed. The background is too pushed, causing the main target to become weak and posterized. Perhaps the HDR step is the main culprit, but also too strong a curve. It's also too saturated, again tending to produce posterization. Narrowband images don't normally need the saturation to be touched at all.
If you do push the background less, the main subject will seem more contrasty and you won't need to sharpen it so much.
I'd strongly recommend you have another go using a more gentle touch, not trying to bring out the background so much, but aiming to let the main subject speak for itself, because the underlying data look really tops. Very nicely acquired.
Thanks guys. I always appreciate the feedback. I just realised pixinsight has not been using my darks, so that may be some of the problem with noise. I wrote some software to interface all my systems together and it writes the fits header, so now I need to work out which keywords are causing the issue.
I'm going to have another go at this data. Hopefully a better result the next time round.