Great, thanks Gizmo!
Now for some very good news.
I fitted a king size bed sheet (whitest I could find) from my ceiling and the colour issues are resolved!!!
White now looks white, blues look lovely and the screen is 8ft diagonal
Theres more work to do getting the colour balance right, not because its hard anymore, but the NVidia drivers dont play nice. Most adjustments are straight forward and work a treat.
At the moment, DVD's, OpenGL games and Windows desktop really look the part. Direct3D colours look washed out, the games seem to ignore my tweaks. This didnt used to happen.
DivX playback looks a whole lot better but is very dark. The Gamma setting will not affect the movie, not sure why. I'll clear all the driver settings and re-install them then work from there.
Fiddling with FFDshow helps a lot, but isnt simple enough and shouldnt be necessary.
My goal is to make setting this up as simple as possible with tweaks in the right places so the colour ranges lose least colour resolution (ie if you make the screen too bright, you get less colours to represent bright things. this makes close colours look the same colour). Changing configurations using multiple tools only serves to complicate the matter further.
I switched to using the projector as my only display (rather than clone etc) as changing colours for one particular screen sometimes affected the wrong screen or both! The above issues with D3D and DivX have started since then. Lots of playing round to do yet by the looks of it!
The drivers I am using are 71.09, time to try some WHQLs.
ps I wrote this in a 4ft box
