I’ve had another crack at this and I think it’s better in some respects, but I’m coming to the conclusion that I really have to get rid of the stars and process them and the nebulosity separately as trying to pull more out of the OIII to bring up the green/blue of the nebula just messes up the star colour.
Actually, I think I probably need to remove the stars and then mask off the nebula itself so I can just work on that and pull up the colour without messing up the surrounding Ha, but my Photoshop skills don’t extend that far yet…