not really knowing what that large, strange stringed musical instument was. But thanks to valuable info submitted to us by Outaspaceman, I can tell you that it's a bass banjo, and that there used to be groups like Raymond and His Famous Banjo Band, a seven-banjo (!) British combo featured in this video of a 1937 performance:
HERE's another video of the group that, to my surprise, did not play bluegrass, but rather, some peppy marches. The banjo was a black American instrument, based on African stringed things like the kora, and was adopted by white hillbilly musicians. I had no idea that, at some point, it made it's way over to the UK and joined the music-hall scene, being utilized in ways utterly apart from American traditions. Learn something new every day, eh, what?