Mick
To save todays refresh i would reckon that the song could have originated in London UK by the reference to Paddington Station .
I would suggest that you pm McGrath of Harlow or someone with contacts in the then Irish immigrant population of London who might remember the song. It looks like a good song and am surprised that it is difficult to trace unless it was written and performed ony by the Benny Lynch led duo
Hope this helps and keeps the thread going even if folks think the theory is wild.