Thanks Steve. Finding evidence of 'Cambric Shirt' in oral tradition in the 18th century could be siginificant. The North American strain of Child 2 seems to consists entirely of 'Cambric Shirt' variants - I'm not aware of 'The Elfin Knight' strain having made it's way over there...

Wrong again! There's one on Richie's site: a 'Blow, blow' version from Phillips Barry. Just the one, though, as far as I can see.