Geoff, the album is "Live at O'Donoghues" (credited to The McKenna Brothers). It was on the Golden Guinea label (GSGL 0441) and was released in 1969.
Fergie, "O'Donoghue's Opera" makes fascinating viewing, particularly the cast of "extras" in the film (Seamus Ennis, Andy Irvine, Brendan Byrne, etc.)