Well, the concept of "Colonel-in-Chief" is peculiar (or do I mean particular?) to the members of the British Commonwealth, so please excuse me if a USAian sticks his oar in. Each of the regiments has one, who may or may not have served in the military.   Hey, gnu...isn't Princess Anne Colonel-in-Chief of the Royal Newfies?   If she has the title, I'd guess that the right to wear the uniform comes along. Now, if she was wearing decorations, that would be another story.