I was watching that Final Fantasy retrospective yesterday evening and I discovered a horrible/excellent mistake I had made.
Despite knowing that American Final Fantasies had been renumbered (4 -2 and 6 - 3) I have somehow missed out the Original Final Fantasy 3 altogether. I didn't even know it existed. For some reason my brain let me think that it and 6 were the same game which makes no sense now...
So I've ended up with a completely new Final Fantasy to play and i'm over-joyed! Embarassed as hell though.