The tune I am sure is included in the book, Picking Sooty Blackberries, which is unfortunately out of print.
The song is however on the double CD of the same name which you can obtain on the Cockersdale Web Site WWW.cockersdale.com.(Sorry not mastered the blue clicky)
Cockersdale have been informed that they have, unfortunately, late last year, retired from clubs, concerts and festivals, however, the good news is there is the possibility they may still appear at a few charity functions.
I wish Graham, Val and John the best of luck in their retirement, they certainly deserve it.