I have 2 Dow albums - 'A Poor Man's Gift' and 'Burd Margaret' - and it is not on either. However, on 'Poor Man's', he sings a Graham Pratt song - 'The Ballad of Lumley Kettlewell' - and says in his note to it that he had recorded a Graham Pratt song on his previous album. That would probably be it, but I don't know the name of that album. That may at least narrow down your search.

--Stewie.