Hi all,
thanks again for all the comments. I've re-processed the image and this time I think it is much more true to colour than the initial attempt at processing the 14-bit images - which incidentially are huge - the final image is circa 100-Megabytes in 16-bit TIFF format.
Here's a 25% reduction of the original
http://www.skylab.com.au/pmsa/Eta_Carina_080515.html
cheers