Alan - You probably know this already, but just in case: There is an article by Edgar Samuel on Vaughan Williams and King's Lynn in English Dance and Song, 1970. It's reprinted in a RVW society booklet here: RVW Journal 14. The article is starts on page 22. It's based on his 1971 thesis of the same name from Uppsala U. I tried their thesis search but failed to see a copy, though I think there's a copy at VWML.

Mick