That's real Prog solidarity!!
Don't worry I did not expect too many replies anyway. Family is quite esoteric, but asking about a specific song is esoteric in power of 2.
I'm not a big fan of the band as you can see from my post. I finally got that Family DVD The Whistler recommended a while ago and after watching it I put on all of Family on my PC. I just "noticed" this bonus version of the song today, looked up the title, and could not reconcile it with the original because they are completely different melodies.
I don't know of any other band using the same lyrics with two different tunes. A different rendition of the same tune is customary, but this is the most unusual thing to do.