defender fuel problem

I have a 1999 TD5 defender with a pump problem.
When the ignition is turned on, the fuel pump relay does not energise.
Then I manually close the fuel pump relay the pump starts.
So the fuel pumps works correctly.
I get 12v on pin 86 of the relay when the ignition is on. (between chassis and pin contact and between pins 85 and 86).
I have checked continuity between the relay pin 85 and the ECU connector, the blue and purple wire.
The main relay and inertia switch are ok.
If I short out the relay to start the pump the engine still won't start.
Am I looking at a knew ECU or can there be another problem.

I would hazard a guess at immobiliser fault, thats why it wont start no signal= no go.

Theres something you can do with the ign key, so many turns etc, try a search.

Have you tried contact spray in the two main ecu plugs?

Do you have access to a fault code reader? Hawkeye, Nanocom, Lynx or similar? That might tell you something in terms of any logged faults and I think there's an option to 'test fuel pump relay' too.

I have cleaned the ECU contacts. I have tested the earth continuity to the ECU case with a 60w bulb etc. The immobiliser light in the speedo works as it should.
I have replaced the fuel pump relay. I have no access to a fault code reader but I am thinking of getting one. Has any one got a recommendation?
Can the immobiliser stop the fuel pump relay from working? i cannot see anything in the wiring diagram. Stops the starter motor form working for sure.