Right, heres the story so far.
Fitted to my Nexia is a 20XE (not C20XE) which as covered 148,000 miles, I have no knowledge of its service history.
In July I had the common fault were the pressure relief in the oil pump stuck open, I didnt run it with no pressure, the pump was stripped and the aluminium internals were quite heavily scored so a new one was fitted, the original oil was strained and I found minute particles of metal in it, new oil was used with new pump, the pressure relief stuck again.
The pump was stripped, it was fine, the oil was strained and was clear of particles, and after reading about this problem I fitted a nylon plunger.
It hasnt happened again, and I changed the oil twice very shortly afterwards and have done about 4000 miles with no more problems.
Today at Well Lane it made 151BHP, and the guy there said that with the mileage and the mods (zorst, filter, FSE)it was about right.
So, do I need to replace it?