It's probably true that the Mellstock Band are an acquired taste. They are an attempt at an authentic recreation of early C19th church bands, of the type Hardy writes about in Under The Greenwood Tree. In fact, I'm irritated to find that their tracks are lifted from the Saydisc album of that name, which I already own - and are Christmas carols rather than hymns. It has to be said they're a bit shrill, and don't always succeed in hitting the top notes accurately.
They're spliced in between two sets of tracks from The Carnival Band's 'Sing Lustily With Good Courage'. These involve somewhat 'folkier', freer-form arrangements including guitar. Maddy Prior sings a lot of it solo which, for better or worse, tends to mean losing the hymnal feel. I found it a bit strange at first, but I've decided I approve.
So, as another reviewer says, caveat emptor; but nevertheless this is an enjoyably soothing, oak-panelled sort of album. It would be great for Christmas.