"Biddy McGrath" is on Matt McGinn's 1968 LP "Honesty is Out of the Fashion" (XTRA 1071--XTRA was Transatlantic's budget label). Alas, it did not include a lyric sheet, so there's no easy way to post the words of the song.

As far as I can tell, the record has never been re-issued, and Biddy is not on any of the "best of" collections.