Thanks for the link.
The video tutorial is exactly what I have been doing, the difference is that there is NO Pro photo option. As it's not shown I can't select it.
There is no pro photo profiles shown in the Mac's colorsync utility either. I assume this is the problem and why it's missing is a mystery to me. Apples support site is no help in tracking down a downloadable new version and running the utilities repair option to drag out badly tagged profiles has not sorted it out.
I have ColorSync version 4.5 installed.
I would install ProPhoto if I knew where to find a downloadable suitable version. As I said it appears in PS CS3 so should have been installed into ColorSync.
Any insight would be welcome.