The December 2023 episode of Matthew Bannister's Folk on Foot looks at Plygain.

This year’s seasonal episode takes us to the village of Mallwyd in mid Wales to join the ancient tradition of the plygain carols. On a dark, cold night, local people gather in the warm and welcoming St Tydecho’s Church to sing Welsh language carols which have been handed down through successive generations of their families. They’re joined by Gwilym Bowen Rhys who unearthed his carol in a second hand book shop and by Owen Shiers (Cynefin) whose singing group travels around several plygain services at this time of year. Asked why she joins in, one singer exclaims: “I just feel part of the ages!”
https://pod.fo/e/20b485