Thanks Mike,Jason and Robin.
I knew that it was not recommended to mix and match bearing caps but I didn't know why.
I'm now sorted with the right bearing shells thanks to a 'very nice man' at
http://www.enginepartsuk.net/. Very knowledgeable and highly recommended!!
If you register on their website you can pull up drawings, etc of the parts and he gave me trade price.
I think I have a bit of an oddity with this engine. It's most definitely from a Feb. 1988 car because I have the 'birth certificate' from BMW but it seems to be of the older M20 design. It has these older type shells, it had long skirt pistons and it also has an old design of the ECU with the two PCB's. Either there was some reason why the registration of the original car was delayed or the engine was lurking in the factory until it got fitted.
Anyway, I'm sorted now so on with the rebuild...
P.S. and thanks again Robin, I know where you are....