.............now with the info that the pump is above the fuel tank..................I am suddenly wondering if that does have something to do with the car suddenly not starting only two hours after filling the tank to the top on a warm day.
Just a coincidence? The AA guy, as I said, checked the flow of fuel to the engine and found it all ok. But is it possible that somehow fuel leaked to where the pump is and caused an interruption of supply that triggered an electronic response?
mmmmmmmmmmm???
I will still go for the crank sensor option first though.
The fuel pump is inside the tank and immersed in the fuel. That helps to keep it cool, and dampen the noise it makes.
They tend to show symptoms of failure when the fuel level is
low, especially if kept that way. These symptoms are exacerbated by shallow, flat tanks like Omega estates(most modern cars really) rather than the deep, upright tank in an Omega saloon.
The symptoms you listed in your first post aren't really those of a failing fuel pump. Those tend to be: poor starting when the level is low and the car has stood for sometime; extended cranking; blown fuses; needing to give the tank a thump to jolt the pump into working; all of those symptoms becoming increasingly common rather than intermittent.