I decided to persevere one split pin and nut and bolt at a time!

End result I have removed the linkage and the governor cover.  In my view it looks fine and once cleaned up and a fresh gasket applied I feel it's fine to leave this alone and dismantle no further.  Any advice would be most welcome.

Present issue is removing the camshaft.

I've followed the service manual instructions to the letter but the thing simply will not come out

Asked a number of associates with relevant experience and they have no idea

Something must be stopping it coming out but what ?

The camshaft is the last bit left in the block ... no cam followers, no governor components, no crankshaft, no lift pump pushrod

Not specifically, but I've pulled down more than a few engines.
What are ya after?

Some photos.

I tried this years ago, decided not worth the trouble. The amount of heat in the exhaust is reduced rapidly under partial load. This is because a diesel always ingests a complete cylinder full of cold air,  and under partial loading, the injection of fuel is just a small part of the complete power stroke, the excess air steals your heat basically.  Using cooling water to preheat the water arriving at a  normal hot water cylinder is a useful addition, but usually requires extensive plumbing alterations and can feed vibrational noise into the other parts of the dwelling. My Lister uses a car radiator mounted through the wall into my workshop, electric car fan ,so does take some chill off during winter. If your engine runs full load for lengthy periods, it may be worth doing, but for me, not.