> which has entered tradition- either through print (Percy) or because Percy took it from tradition

Just a quick thought on this one. Percy says that his version is "Given, with some corrections, from an old black-letter copy…" But he also says, in his preface, that sometimes he has only mentioned one or two sources for a ballad, when he has actually used other as well. In this case, my guess for what it's worth would be that "corrections" means that he revised the text to bring it more into line either with what he heard someone singing, or, I think more likely, with more recent broadsides that he preferred not to mention – he was offering his readers ancient "reliques", and it would have spoiled the effect if he had let on that they could pick up some of the stuff at any street corner. Of course that presupposes that things like the name Jemmye Groves and the "Farewell, she sayd, ye virgins all" stanza were already in circulation, either in oral tradition or on broadsides that are now lost, but given how much of the evidence is now lost without trace, I don't see that this is too improbable.

The other mystery I see here is the relationship between the various J… Gr… names. Assuming that the similarity isn't coincidental, did Barbara's lover start out as Sir John Graeme and then go down the social scale to become plain Jemmye Groves etc., as the order in which the names turn up in the surviving written record might suggest? Or could it have been the other way round – part of an attempt to rebrand the ballad as something grander and more Scottish? I guess there can never be an answer to that either, unless an even earlier written text turns up somewhere.