I have often wondered about finding if The BBC were open to releasing local archive material. Back in the early '80s BBC Radio Sheffield recorded most of the concerts at Stainsby Folk Festival (or accessed the recording if a private firm did it, my memory is dodgy, I just recall taking shop with a man playing with a Revox B77 similar to one I had) and this included a wonderful set by Diz, followed by him and Johnny Silvo playing together.