Hi Graeme,Did you already notice that Apple's "Profile First Aid" (ColorSync Utility) moans about missing tags in Argyll XYZ CLUT profiles?:
Tag 'rXYZ': Required tag is not present. Tag 'gXYZ': Required tag is not present. Tag 'bXYZ': Required tag is not present. Tag 'rTRC': Required tag is not present. Tag 'gTRC': Required tag is not present. Tag 'bTRC': Required tag is not present.I'm not exactly well versed in the ICC specs but I think Apple is wrong. Also SampleICC's iccProfLibTest tool attests that the profile in question is valid.
Klaus