I had the good fortune to be booked for the ex-submarimer's reunion weekend at HMS Dolphin in Gosport many years ago.
Shep Woolley, Bernard Wrigley and myself, but the highlight of the weekend was the Sunday afternoon with Cyril Tawnwy and although they were not your usual Folk club audience, they knew his songs and joined in with them.
Cyril Tawney and Pusser's Rum a combination I'll never forget.

Thanks for the info about shale, I thought it was something to do with coal.