Thanks Clive, yeah plenty to work with.
Here's the Sidonio. Several blendings with masks to emphasise details and areas, a bit of sharpening applied to the flame and areas around the horse and a final noise reduction with Neatimage. Mike's advice of using much less of a heavy hand with the stretching really shows, retaining detail in area that were previously white clipped around the Horsehead as well as the flame nebula. Gives a sense of accomplishment. Thanks all.
A small image or a full size if you care for a peek.