In reply to MtheGM, what Jeannie Robertson sang was called 'Little Matty Groves' (confirmed in the book 'Emergent Singer, Transformative Voice' by James Porter and Herschel Gower, about Jeannie). Obviously it was sung as a Scottish version, but I recollect hearing - presumably from Norman Buchan - that the tune was adapted from one sung by Jean Ritchie for the same song at an Aberdeen Folk Festival around 1960, which Jeannie heard and liked.
And there is a suggestion in the Porter book that Jeannie, in fact, had two tunes for this ballad - one that she regarded as her 'big' tune, which she would only sing when properly warmed up. Having not heard Jean Ritchie's tune, I've no idea which one I heard that evening in Norman's house, which - in any case - I've now further adapted to fit the different version that I now sing.
The everlasting folk process...