Oops. Forgot to respond to the nonsense comment. Not to be confused with nonsensical comment, of which there are none in this thread. Barring this bit of course.
Anyway, I don't know if the nonsense choruses in the two versions differ, but I'll see if the J.Lloyd Williams book is in the college library here. (It's one of those texts all us amateur folk historians are supposed to read ... ) It wouldn't surprise me if they were different. If you and I both learned a ... Yiddish? ... song by ear on separate occasions and happened to meet up 20 years later, I imagine the versions would be vastly different. And anyone who spoke Yiddish would be rolled up in a corner laughing themselves sick.
Welsh is *completely* phonetic, once you learn the rules, so you can see where the nonsense comes from ... sort of. I'd think it's something like,
(twigar owns again stumps me - thinking of the railway connection: stoke her once again?),
the Poacher and the Piper on the Knickerbocker Line. La di da di da di
Hock it (?) on the chain
The Poacher and the Piper on the Knickerbocker Line.
But I guess that's easily checked by referring to the Peter Kennedy book. Guess that better go on my Christmas list...