The question re Anglo v English concertinas is intriguing. I would say yes, you could pick tracks from the two kinds that would point up the difference very clearly. I am not, however, going to make a suggestion as to which tracks, I'll leave that to concertina players.
May I make a suggestion that you mention the banjo in the course of your talk, an often neglected stalwart of the country dance bands. The greatest living exponent is Robert Murch, get a recording of his with Dan Quinn(I think they have a new group called The Talk, but I may be wrong. It might be the Walk, or something else unlikely).