I know this is an old post but I just joined and saw it, so I thought I'd write. I'm a British car enthusiast and I know the British Leyland B-series engines well. So, if you need any help identifying or finding parts, send me a message and I'll try to help.
A lot of the smaller parts, gaskets, etc, on your engine will be common to the gas versions used in cars too. Any MG sports car specialist could help you out.