Glad it worked.  This is not a good week, so far, to be searching for things!  A little more background:   So far as I know, the melody of "O If I were where Gadie Runs" (also known as "The Hessian's March") first appeared in print around 1820, though the tune is presumably considerably older, and the earliest set of words for it is traditionally ascribed to Arthur Johnston (born 1578).  A version of the song was put together by one John Imlah (1749-1846) of Aberdeen; presumably the putative ancestor Hamish Imlach spoke of.  A.L. Lloyd had this to say about the tune:  Probably the widest known version of the tune is the one commonly attached to the nursery rhyme: "If I had a donkey that wouldn't go, Would I beat him? Oh no, no".

(Information from "My Son David" and "O gin I were where Gadie Rins": A note on Tune Relationships and Local Song-Making"; David Porter, Folk Music Journal, vol.3 no.5, 1975).

Malcolm