'The Truth about Chrismas Carols'
BBC4 Tonight 2000

The documentary celebrates the enduring power of the carol with a variety of performances from folk singer Bella Hardy to the choir of Truro Cathedral.

https://www.bbc.co.uk/programmes/b00gbgt3

I wouldn't normally watch anything entitled 'The truth about..' or 'The secret of...' but this might be interesting.