So here we are again searching the depths of the wisdom.

Defender 110 TD5 2000
Tis dead and about to get drastic action - matches

My Hawkeye tells me my only fault is EGR (which is removed)
But live readings tell me RPM error. I can also get live RPM readings, i.e. my cranking reading at about 200rpm.
Could this error be the last reading when the car shut down of it's own accord?

you should check the fuel delivery system as it's not cobvered by diagnostics,... do you hear the pump running?

Pump is running.
I need to drag the car to work and stick it in the big shed.
I have a fuel pressure gauge made up using the old pipes from a fuel regulator. So I can plug it inline and check the pressures.
Seems a coincidence it reoccurs when wet?