Thanks Jonathan,
My footage is Uncompressed 8-bit YUV codec QT’s straight from an animation house (footage is not live action, but an animated show).
I’m not as concerned about my Mac monitor as the colour shift is evident on a calibrated external client monitor that we have. I think we’ve found a solution though.
I’m now exporting the shots from FCP as their native Uncompressed 8-bit, then opening them in PS and adding a Levels input adjustment of 16 and 235.
I then make my fixes and export the QT from Photoshop as a None compressor, and import into FCP.
In FCP, I add a Gamma correction of 0.82.
This procedure seems to negate the colour shift. (except in the reds a little bit)
A bit of a pain but it seems to work
Thanks for the suggestions Jonathan!
Rob