I can think of very few British traditional players who used guitar. "Peerie" Willie Johnson from Shetland, of course, and I've a photo in an EFDSS magazine from the '60s of an Orkney trio comprising fiddle, accordion and slide guitar. The Norfolk melodeon player Percy Brown was sometimes accompanied on guitar by his son-in-law Fred Devo. No doubt there were others, but the guitar never found a place in traditional music to compare with fiddle, the free-reed family, flute and whistle, or even bagpipes.

It was the folk revival, influenced by American music, which saw the introduction of the guitar in large numbers into the folk clubs. There's no question that among folk revival musicians the guitar has a significant presence. However in the absence of any traditional British styles the British folk scene has developed its own, which makes considerable use of open tunings - of which DADGAD is just one.