Important point above, that the More, Moir, or whevs, element of the hero's name is not a surname, but an emphasis of his size. Same usage will be found in such names and phrases as Glen Mohr, the Great Glen; the Gillie Mor, the Big Man, &c.

So the title Lang Johnny More actually means, Tall Johnny, the Big-Yin [as Billy Connolly told me he was called in his Glasgow youth ~~ "Excuse Me, Big Yin" was the title I gave my interview with him in Folk Review, October 1978; & Wikipedia confirms it as his standard nickname].

~M~