Name that tune

The SSC are a Scottish youth group who run camps at which sports and games are played and at which songs are often sung of an evening. Many of these songs have been handed down from one generation to another. Recently I was given some hand-written ("written" may be too strong a word in places) scores for piano and vocals. I attach one one them that I have fleshed out and MuseScored. Opinions vary as to the source of this tune. To me it is reminiscent of some of Claribel's stuff ("I Cannot Sing the Old Songs" etc.) but I wonder if any Forum members know what this one is dervied from?