Have you had a butchers at the earliest broadside versions? Roxburghe Collection has at Vol 7 p59 (Just been won on Ebay) 'The Three Worthy Butchers of the North' printed by Phillip Brooksby c1675. It is set out in 10 stanzas each of 10 lines. A slightly later version is given on p62 which is reduced to 11 double stanzas then as it gets passed down in the print tradition over the next 2 centuries it comes down to 9, then 8, then 7 double stanzas until on Irish broadsides it is just 10 single stanzas. The writer of the ballad is given as Paul Burges on the Brooksby sheet. He gets in everywhere! There are lots of 18th and 19th c versions on the Bodl site.

Hmmm! A difficult one to say if it's true or not. It is certainly set out as a true story. The murders were discovered by a shepherd hiding in the hedge and the robbers escaped abroad at Yarmouth. Ebsworth, usually very reliable states 'We doubt not that it was genuine history, truthfully told.' That's good enough for me. In another shorter but early version the girl is captured and punished.