Wild Mountain Thyme / Will Ye Go, Lassie, Go

This is about the most confusing song I've had to deal with. It is clearly copyrighted by Francis McPeake (in the 1950s) through an English folk music organization, but the McPeakes appear to have been unable to assert their intellectual property rights (even in court) due to the song's connection to earlier compositions. When I posted a video on YouTube, I was prepared to take it down if challenged, but no challenge came. There is even a small handful of videos of it on FOTMD (Are they okay, or did they slip through?).

I want to post WMT here as a challenge song, but I don't want to break any rules. O, administrators who administrate, rulers who rule, and knowers who know, please share your wisdom.