I have the music in a small book of a cappella favourites for mixed voices by Jean Harlow in the Sing for Pleasure series. It is described as an Irish folksong, collected by Chris Green and arranged by John Coates. This arrangement in for Soprano, alto and bass but I have had to rewrite it in SSA for a ladies' choir.

I got it from the BKA (Britihs Kodaly Academy) bookstore, which supplies a whole range of vocal music: www.britishkodalyacademy.org. If you want to browse for this and other folk songs, you can have visit the bookstore at the BKA's summer school (12-18 August this year). I don't know if it's still available but if you're hunting for an SSA arrangement, please contact me at hintez@btinternet.com

Hope this helps!