There is a tune quoted in George Butterworth's "Two English Idylls" which starts out very much like the 17th century Scottish song "Good Night and God/Joy Be With You All" (better known in its modern adaptation as the Irish pub song "The Parting Glass"). I didn't realize there was an English version of it, but given the context, there must be, since Butterworth's piece is based on real folktune quotations. What is it and where did Butterworth find it?

First appears around 1:15 here:

https://www.youtube.com/watch?v=T3mNhod6W7c