Tam Lin is a Border ballad - please allow us from those parts some ownership of such a magnificent tale. Actually Lloyd does mention Tam Lin in "Folksong in England" in The Big Ballads section(he spells it Tam Lin too) but only refers to the story and does not publish any of the text. However in "Journeyman" MacColl gives a few pages over to the balled and also publishes a full version of the ballad which is pretty much the variant that I know. I have heard both MacColl and Lloyd sing versions of "Tam Lin" live but the first person I ever heard sing it was Paddy Tunney.