I had some converted HD M2T's > Cineform DV size (letterboxed) with .mov wrapper on my PC. I then took these to a Mac to use in Final Cut, after installing the Cineform Mac codec. After viewing in Quicktime fine, I opened them in Final Cut, but there is a strong blue hue over the image which looks totally off.

Any ideas how to fix this?

I've seen some frustrating gamma shift issues but never a color shift. QT gamma inconsistencies are well known. We've not seen color shifts in any of our testing. Please file a ticket and submit the files so we can take a look. We're actively working on the QT idiosyncrasies right now and we'd like to check this out.