As stated in an earlier post, uillean pipers make much of the flatted seventh. Perhaps I ought to give up looking at publications for singers, and look at piper's music publications instead. But that still doesn't tell me where Ní Scolaí, and O'Hara a generation later, found that melody for
"tiocfaidh me 's ní fhanfaidh me."

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Probably because it had been in the musical tradition for hundreds of years already...it is like one of us looking for a written version of yankee doodle. we think we know the definitive version and there is a very standard version we mostly keep to...