I had got into the fringes of Folk and then fell into the Blues thing in early '65 , when I discovered that it was easier to play a twelve bar in E on a cheap D whistle than on a soprano sax ! December '65 the almost blues band I was in was on Television !
A LOT later I saw Gary Davis a The Troubadour (When Long John Baldry was Roadying) - I wuld have loved to have a jam with him , but I dont think R G D had ever met a Blues Whistle player !