I learned it from my Dad, nearly 50 years ago now, in the southwest of Ireland, but it was just the first verse (shoeshine shop) and was spoken, not sung. He also had another (spoken) potentially naughty tongue twister which went as follows :
"I'm not the pheasant plucker.
I'm the pheasant plucker's son.
I am only plucking pheasants till the pheasant plucker comes!"