Also, Robin, you haven't said where you're at. If you're in NF, there's plenty of people you can look for to help you. Memorial University folklore department, to start, but also the likes of Fergus O'Byrne, Jean Hewson, Don Walsh and Jim Payne are kicking around St. John's a good part of the year. GBS learned many of their songs from the likes of Fergus, so he'd be a natural interview...I think they adapted "Jolly Butcher" from Jean's version, and Jim and Don were working on a CD ROM version of the Peacock book last I spoke to them.It might make sense for you to call the folklore department at Memorial anyway and see if they can help you. Phillip Hiscock in the archives has a pretty strong knowledge of the field-recorded legacy of NF outport songs, and the boys did do SOME of their research there...
other books:
Maud Karpeles: Folk Songs from Newfoundland
Genevieve Lehr: Come and I Will Sing You