As I typed from the outset, I am no expert and fortunately have never been required to get physically involved in the disassembly of any Rover V8 oil pump, other than to replace a failed oil pressure switch which controlled the electrical supply to the fuel pump relay as a safety circuit.
Given the above, I lack the anything like the amount of knowledge you have amassed on this and many other Morgan related issues Lorne.
I typed that I had doubts re the PRV causing the issue and detailed the reason behind that line of thought, I look forward to being proven wrong... and not for the first time... (-:
Using an oil can to prime the system via the removed oil pressure sensor`s orifice, and using the oil pressure gauge to provide some measure of success or otherwise before spinning the engine over, would be my go-to method... Tried and tested and proven on two of my own engines that did not build oil pressure after aspects of engine overhaul..
Whether there might be access or not on a Y2K +8, to work with an oil can as suggested, I have no idea..
As I have already typed, I care not which method Jeremy might care to make use of, I just look forward to reading that he is up and running with no issues...
