I also had matched third party notice on Greensleeves. I challenged that and my challenge was accepted. I've recently had a matched third party notice on another traditional Irish song "The Dawning of the Day".

It seems quite common to get these notices on traditional songs. It's time Google set up a filter to weed out the common obviously "silly" copyright claims such as for Greensleeves which is well known to be old and clearly in the public domain.

As a matter of principle, I always challenge copyright claims on public domain songs.