I meant to get back on here to say thanks for your reply Lighter!

I should have explained more clearly - Máire Johnston didn't claim to have heard the verse in 1885 - indeed she was not born at this stage and only wrote the book in 1985! I get the feeling that she heard the verse at some stage growing up (the book contains many snippets of such verses) and being unaware of the various precedents, presumed that it stemmed from the said visit.

Hope that clears things up a bit and sorry if my original post was misleading!

Regards,

Ian