Well, it has been suggested that costermongers were originally Irish - as indicated by a quote in Ben Jonson's -play "The Alchemist", back in the early 1600s "Her father was an Irish costermonger"...

And costermongers of course have been the archetypical cockneys, and Harry Champion who sang this song was the archetypical cockney...

And that's about as strong a case for "Any Old Iron" being Irish as I think can be cobbled together.