"British Isles" includes Ireland (though some object to it), because it's a geographical expression. But "British" never does.

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The "Kilgarry Mountain" version is presumably a reimport from overseas, since there's no such location in Ireland. "Far famed Kerry mountain" is in Colm O'Lochlann's 1938 collection, as learned in childhood.

The Lily of the West is also there - if that's an import from America, it's not a recent one.