The "entity" (sounds like something from Ghost Hunters) that claimed copyright content on God Rest Ye is called Music Publishing Rights Collecting Society. A little digging reveals that these people routinely file this veiled threat on thousands of videos including one self-described by a kid named Tony as "me playing ping pong". Often, Youtube/Google's immediate reaction is to place an ad on the video and,I suppose, immediately begin monetizing "Music Publishing Rights Collecting Society". This smells like a scam to me, and I'm ignoring them.