It is indeed a Scottish song.  See this thread from last October:  Ploughboy Lads,  where I posted Jeannie Robertson's version, and a transcription of a recording by the Black family, who learnt it from her but changed the words a bit.  There is also a link to a midi of the tune.  "Gambol" would be "gey weel" if the Dubliners also got it from Jeannie, which seems likely -though they appear to have re-written it to shift it into the third person.  Perhaps they felt uncomfortable singing from a woman's point-of-view.

Malcolm