This is beautiful! I just went to listen to the original and I will be getting some of their music.
Man, I can remember back to my choir times and some attempts at things like this, small groups playing with sound. Some of us did beat boxing and we would mix those sounds with more traditional vocalizations, but this is just great.
I had a great teacher too. We would play with music often and it sparked a love for it in me I am always thankful for.
My favorite part was watching some of their faces. Not only were they having a good time, but they were there, "in" the song as choir can do when one opens up to it. Excellent. Somebody in London deserves a gold star.