Just to clarify - if you re-arrange, structure and add original lyrics to a trad work, then under law it will likely have a copyright no matter what you may think. Creating a chorus structure with lyrics, is adding originality.   Lyrics have a copyright in their own right,   However, if that work has a tune that is provable as trad. (0ver 70 years since the writer died), then the tune can equally be re-arranged and claimed by anyone. I'd love to hear how close this printed work here is, as all versions of Braes that I have heard have no resemblance to the 'modern', Mcpeake version. This subject has already been covered at length.   A similar issue arose over a court case involving 'Westering Home', and a derivative called 'Travellin' Home.'. which were both modern copyright works based on a trad. tune.