Following the results with the other injection systems I decided to lap the delivery valve on the diesel and have another try. The initial priming was much easier and the results with the 10° nozzle were encouraging.
The 15° nozzle resulted in a runaway.
After this it wouldn't inject or start again

I suspect that the injection pump plunger has overshot and jammed
I am currently working on a slightly smaller helix type pump which should reduce the inertia of the pump components. I am also thinking about converting this engine to a four stroke for some trials. It is much easier to separate the various influences.