Update - So the hard drive still didn't work after cloning it and reformatting it.

However when I removed it again - the navigation has once again become greyed out and the cic unit no longer restarts - I haven't got time to go and drive it, so not sure how long this will last.

Any solutions would still be appreciated - would deleting the Navigation - US option in NCS force the CIC unit not to always have the navigation greyed out?

Cheers