Been held up with the big problem . How to repair the broken M6 bolts , there are 28 of them broken off in the side of the engine block. The jacket side cover has 32 of the M6 bolts and 28 of them have broken. This is a common problem with this type of vintage engine.
Looking into the options I have decided to drill out the bolts and use M6 heli-coils. This process requires very accurate drilling...more about that later on.
Good fortune: I found a 1930s era film made by Morris Motors (Morris had their own in house film unit). By a stroke of good luck the film depicts a Morris 6 cyl. engine , drilling and assembly. Basically it is the same engine that I am currently working on ! The film reveals how they drilled out the 32 holes in one process, and to such a high degree of accuracy.
https://www.youtube.com/watch?v=ieF3d_YBUh4
Another issue I have is: a replacement head gasket. As of now, there aren't any replacement new head gaskets available, only a very few old stock gaskets exist and these cost a small fortune and are of dubious condition. I believe a few Morris 25 car owners have had gaskets hand made. I have made enquiries to overseas gasket makers, the prices are very high, maybe a run of 50 would be viable.