Noreen - have a look at the recordings page as there is a CD by the same name, which gives a good indication of the material. The show combines music, interspersed with seasonal readings from the writings of Thomas Hardy, Laurie Lee, & c. - and a Christmas Mummers Play.

They are incredibly versatile and you an expect to hear 25 instruments plus their five voices - woodwind, brass, stringed instruments (plucked and bowed), free reed and percussion - and have a good laugh into the bargain! Sounds fine by me!