Joe - in the 2 copies of Politick Wife I linked at the Bodleian the 1st has no date, the 2nd is dated between 1736 and 1763. (Dates when available are on the search result, but generally aren't particularly exact - a range like this is typical, even quite narrow compared to some).

Reinhard - thanks for the quote for the Folklore article.

Fred - I think both Martin's sleeve notes and the Folklore article are telling us that Bert made a singable version of the song from Buchan's text. Looking at the Politick Wife, while clearly not the same as Martin's text, portions of them match closely enough for me to believe that Bert's version came from a song source rather than made directly from the folk tale versions. It would be nice to have the Buchan text to compare, then we'd know how much rewriting he did!

Mick