Hi guys,
Thanks for your advice. Yes, I have Photoshop CS 5 and LR 3... and I've tried to do the gradient removal process as you describe, but I can't get my gradient to match up with the light pollution gradient - so it results in weird artefacts.
Alan & Ivo - I like your efforts so far but I think they've inadvertently removed some of the real nebulosity in the Milky Way. Here's a screen shot from
http://www.skysurvey.org - you can see that the Southern Pleiades area has the darker brown/gold nebulosity while the central area with Eta Carina has a lighter shade of nebulosity.
Showing this in my image is proving rather challenging!
Dave