Thank you for your comments re. Fuel Pump Problem.
The flow coming into the pump seems fine (full bore on the inlet pipe from tank).
I'll try your suggestion to loosen the cold start button then have a look at the rack movement.
My feeling is that the lift pump is not working as it should (no pressure when pumping), and yes I do know that you need to crank the engine to get fuel past the injector pump (but in this case no fuel coming through).