The piece starts at 19 minutes. At one point in the interview (@ 36mins) Sean Cooney says that Bellamy's Ballad of Henry and Suzannah - the verses he sings to link the songs - "somehow detracts from the story". But in the next breath he says that if the audience don't pay attention they won't follow what's going on (my paraphrasing).

Bellamy's concise linking verses certainly don't detract from the story, but do presuppose the listener will know some history: about girls going 'into service', that a minor crime could result in hanging or transportation to Australia, or what a 'stage' is for a mail coach. And I think they think a modern audience will not know enough history to understand the context of the songs - especially in a live performance. And I suspect they're right.

So having spoken narrative is justified, I think. It also addresses the problem that Paul Sartin mentions at the start - the original is too short. It also allows them to widen the scope to cover other, different, forms of migration. Which really does 'detract from the story' in my view.