Not found on any of their albums, but from the B-side of their famous hit single Gaudete
And for even more fun:
I didn't hear this version as a youth - but it was released as a single in 1971. Martin Carthy takes the lead vocal.
Now, why is this so very good? 1. Carthy is a genius. 2. The arrangement and backing singers are superb. 3. Although in a sense it is a parody, being an unaccompanied folk version of a 50s single with exceptionally banal lyrics - it is done with absolute seriousness and performed at the highest standard of polish.
(It is a common but fatal error to imagine that parodies can, or should, be done badly; when in fact the better they are performed, the better they work. I once saw (in a Newcastle Dental Students Revue, 1977) a really amusing take-off of Glenn Miller's In The Mood done with kazoos to replace the brass and saxaphone sections - with the kazoo players thoroughly rehearsed; standing and sitting in groups, and to take improvised solos, just like 'the real thing'.)