I've made some small tweaks to the image to cut back the black point a smidge and to tweak the star colours. This version is certainly more aesthetically pleasing, to me at least, and I don't think that I would be wanting to push it any further.
Link to revised version on Astrobin is here.
The star colours are still an interesting point of discussion and I want to lurch into a discussion on this to help me understand it a bit better.
I am concluding that the white/blue stars in the image are, just that, white/blue. Checking in Stellarium for most of the bright white/blue stars in the core of the cluster reports that they have a colour index in the range of 0.50 to 0.60. I haven't found a definitive resource yet to help me conclude categorically that a colour index in this range should result in the colours that I am seeing but indications are that this should be so. I have attached an annotated version of the image which includes the B-V colour index for a number of the stars (information extracted from Stellarium).
Comments from other persons on this forum that are far more learned in these matters would be much appreciated
Rodney