4ADiva - thank you very much for the link and your transcription work. I've been hunting for this for several years since seeing it performed at Warwick Folk Festival. It appears that the lyrics have evolved a bit since then. I'm pretty sure it was "the one our Trevor left you", and I recall a phrase - "the tunes you play, all sound the same, can't tell the difference." I'm not sure where that fitted in.

And Leeneia - my concertina playing friends that have heard this like it. Jokes are directed at banjos, bodhrans, accordions etc. They're all taken in fun and the aim is to retaliate with a better joke.