Jag wrote -
"Before revival did it matter that singers changed songs, as they clearly did? No more polishing of stones allowed? "

Your Honour, I would like to plead Not Guilty to the charge of tinkering with songs but Guilty to the charge of cobbling different versions together.
I was fascinated by The Unquiet Grave but could not find a set of words that seemed to flow easily and still tell the story. I can remember sitting at my kitchen table with 5 or 6 books and sleeve note transcriptions open at the correct place and taking a line from here and there, sometimes a complete verse, not adding a word of my own until I came up with something that suited me.
The tune I took from a recorded version of the ballad from a banjo-driven American version which I slowed down and loosened up rhythmically so that it suited my unaccompanied singing.
I remember singing it at a ballad event at the School of Scottish Studies in Edinburgh. At the end one of their staff, now deceased, rushed up to me with questions about where I had found the best version she had ever heard. The look of disappointment on her face when I explained how it has come about was palpable.