Quizmonster - you're in good copmpany if you get all his names mixed up - didn't Diana do the same thingwhile reciting the marriage vows?
As for bonnie Prince Charlie... as noted recently on the site, his granddad George VI was born Albert Frederick Arthur George and moreover, to make us all wince at their stupidity, he actually had a brother called George. More than enough to make Michael Jackson (father of Prince Michael, Paris Michael and Prince Michael II) seem almost sane. Certainly precedent for Charlie to call himself Prince Whatever.