Not a direct Ewan story, but relevant here I think.....
Very quickly after getting into folk clubs in the early 1960s, I was smitten - still am - by the magnificent singing and repertoire of the various Scots Traveller families. This was before I heard the radio ballad The Travelling People which remains a favourite with all those magnificent songs. Soon after hearing the album, I started to spend summers in Scotland and was in contact with various traveller families, mainly the Stewarts of Blair who were so wonderfully welcoming. I started to find in long conversations with Belle that lots of the phrases and constructions that she used had also been used by Ewan in his compositions for this radio ballad. Somehow, this made me feel uncomfortable.
About this time we booked Bert Lloyd at out folk club and he stayed with us after the club which was the usual pattern. I used to love talking to Bert, who I always regarded as a very wise man. I mentioned the fact that I had found many of Belle's phrases in Ewan's songs and that I felt that this was in some way a form of plagiarism.

Bert listened carefully to what I said and then answered, "Perhaps what you are describing is the great skill of the man."

Hmm... oh yes....hadn't thought of it that way.