I had always presumed that this was a spelling mistake and that they were one and the same person, then I heard two songs (don't ask me what - I can't remember) and the accent was quite different, one being sort of American (Canadian?) and the other Scottish. This cast doubt in my mind. (Of course my cloth ears hearing accents that aren't there is yet another possibility)

I was hoping that someone here would know of the top of their head if there were two. It's looking like there's only one!

Cheers