A few observations . .
1) The Liza Carthy version of the song I know from the Banddogs LP (see recent threads re; Dave Bulmer/CM, Nic Jones and Tony Rose . . I think it's been mentioned in it); I think Chris Coe (of Ryburn 3 Step - at Sidmouth this year - and formerly of Banddogs) still sings it also.
2) The definitive version of Shoals of Herring has to be the one from the Radio Ballad - which, remember, is now available on Topic CD.
3) I have a tape of a radio broadcast of MacColl/Seeger where Ewan boast of the fact that, since he wrote "Shoals of Herring", it has been collected back "from the tradition" a large number of times and in multiple languages. (Sorry, I can't remember the numbers, but Ewan could exagerate such things anyway . . )
4) By the account I have of Sam Larner's claim to have known the song all his life he was trying to "grope" Peggy's knees at the same time . . taking advantage of his wife's failing eyesight . .
G.