COUNTRY BLUES - Billy Connolly with Bert Jansch 

if I'm not mistaken, Appalachia was populated/settled mostly by Celts ie Scots, Irish and Scots-Irish

I had no idea.

At some sort of Billy Connolly tribute, Bob Geldof came out with a remark, meant as a joke, that Billy was the worst banjo player Bob had ever heard. The jollity drained out of Billy's face. You could see he was hurt. Later that week, he was on Folk On Two, and Mike Harding made a big point of celebrating Billy's banjo playing. I'm sure he felt the record needed putting straight, and Billy should get the credit he deserved and from someone who knew what he was talking about.

all the best ones are like that.

Isn't he! Properly, surprisingly good.

And Bert got it from Annie Briggs. But he paid her in kind, it is said.

They nicked a lot. e.g. Babe i'm Going to leave you

Scrapper Blackwell and just about every other delta blues musician I can think of as well.... But, done only the way led zep could.

It’s there if you listen carefully for it.

Which is interesting cos this sounds much more like the Boggs version