Yet the first DT version (filename[ SHEATHKF) seems a most commonly recorded one now. I've just happily received:
Schneyer, Helen Bonchek. Ballads, Broadsides and Hymns, Folk Legacy FSI-050, CD (orig. 1974), cut# 11

I've thought about the MacColl one for years but Schneyer's wunderfully restrained yet dramatic cut says I gotta finally learn the thing.

Except for one or two words and punctuation it's identical to the DT version & basically the same as Tony Rose, Maddy Prior et alia http://www.gaudela.net/prior/flesh_and_blood.html#sheath

Schneyer says she stole it with violence & menaces from John Roberts.
Somebody (say, in Maine) please ask John where he got it.

Since this thread left off, the fine Loomis had started but gives nothing new at the song.

Bronson isn't mentioned above but adds that the song is rare & never collected outside Scotland and that only in the 1st half of the 19th cent. The only tune (a "plaintive" one) is the one "salvaged by Burns" and printed in Johnson's. A later version of this tune was collected with different words.

My feelings about MacColl was that he was remarkably true to his text sources on record. Even when I was sure he'd screwed up because his text was so very unlikely - he was still true to the source as it turned out. Just using a version I hadn't read before.

As to Scottishisms, I can easily understand if he screwed up from time to time. A trad version may vary internally in word usage - say "if" in one line and "gin" in another - "go" in one line & "gae" in another. Scots generally have several dialects to choose from when singing. Further, in Ballad Scots the regional accent & consistancy of pronunciation generally disappear. I certainly can't always remember which regional variation a particular commmon word is in in a particular song version. I'm more likely to make my Scots consistant than source singers often are. MacColl had a better memory than I do but still...

And who's to say the source or source's notifyer got it "right" in the first place?