Dear Patrick,
I can tell you. Back in 1975 I was a college student on an exchange program in London. One of the reasons I went was because of my fondness for British Isles folk music. I had Nic Jones' first two albums (there was a huge gap between them and Noah's Ark Trap, which didn't come out till '77). Anyway, Nic played Annachie Gordon as his last song at a folk club. I was sitting a few feet away, watching his guitar playing. At the end of the show, I asked him what tuning he was in and he said CGCGCD. I immediately went home and started trying it out. I still can't quite sound like Nic did playing style wise (he was one of a kind). Glad you asked a question that I could answer.
--Phil