I realise it is an old thread, but just for the sake of completeness, I would like to refer back to Nigel Parsons (earlier in this thread).
The song as sung where I grew up (Bradford, West Yorkshire, early 1960s - Catholic school) was identical except the line in the refrain, which was E-I-Endio, not Adio.

I have on occasion wondered if there was any explanation for the two variants.

Quack!
GtD.