I didn't take too many photos, but here's what I did or ran into.
To take out the radiator, you have you take off the push bar, mesh guard and wind tunnel - in that order.
Drain the radiator and undo the radiator pipes top and bottom so the radiator can be pulled out towards the front. The hoses will need some wriggling as they likely have rusted to the radiator, pump- and head outlets.
After disassembly, I cleaned the radiator and the upper radiator pipes. I thoroughly flushed the radiator with tap water until only clean water came out. The small overflow pipe running down the side of the radiator needed poking with a wire and then compressed air and water to clean it up.
The ends of the pipes which are held in the rubber hose connection pieces were rusted so I cleaned them up with a wire brush and have repainted them before refitting.
I disassembled and lapped the surface of the tap to make it watertight again.
The radiator hoses were replaced at some point in time with generic Gates 45-mm inner diameter hose, they are still in good order so were cleaned up for further use.
I plan to put the radiator back in and then fill it with tap water to flush out the engine. This will probably take a few cycles to clean the engine from old coolant. Only then I will fill with fresh coolant.
Currently working on changing out the distributor with an electronic one. Working on the ignition with the radiator out is so much easier!
To be continued.
Original part number "91C-8290" stenciled on the upper radiator pipe:
