The Scottish versions of the Child 279 "The Jolly Beggar" (and other names) are old (in the Bodleian is an explicit version dated between 1774 and 1825 (Ballad Catalogue 2806 c.18(171).

The tune to the Irish Johnny Dhu-Little Beggarman I am sure is an old fiddle tune (pretty well verified by Richie, above) but I was trying to pin the Lyrics.

I am not sure that it has a relationship to the Child ballad beyond the fact that it concerns another beggarman. It does not emphasize sex with a young maid and the protagonist doesn't turn into a gentleman (with his band of knights) or the duke of Argyle, etc. Is it any older than the singing of "The Oul' Rigadoo" by Lyons at the Coleraine Music Festival (Joe Offer, above)- when was this?
Still confused.