Geof. I'm not sure about any sealing but I propose to fit bellows-type coverings on each end. There was a metal covering but I'm not sure exactly what purpose it was supposed to serve.
I was investigating bellhousings and contacted Dellows Automotive and happened to speak to Jeff Dellows and it turned out he lives in the next street. He dropped around to have a look and he pointed out to me what was going on.