Ow well, I have put my attempt here but I'm not sure how long it will stay there or whether I've aligned things correctly - I have to admit to being out of my depth with this one...

I had also realised after my last post that we didn't have a "real" source for the words I was using and that would be breaking the rules at folkinfo.

Maseto has kindly provided me with scans from the book he had taken the tune from and that would have been ideal but unfortunately the words are reading to me as a phonetic attempt to show Welsh for an English speaker. Here is an extract:

Me seeth vach-gen ye-yank foll
Un b'you un ol vuh fon-cee

Maybe a Wesh speaker could assist?

Jon