Focus erratic starting issue

Hello,

Hope there is someone who can help. I have an 02 focus 1.6 (petrol). It has had a number of instances where it refuses to start after a run - originally it seemed to be after a motorway trip but now I think it is simply after the engine has got properly hot ( stop start traffic etc). It will usually fire up and then die through fuel starvation - no codes recorded in the ECU. It will usually start maybe an hour or so later without the slightest hint of a problem, although there was one instance when it would not start 5 hours later, but, after I'd towed it home and got it on the drive - making me think that the physical jolting during the towing may have "cured" the problem - it started first time. I had one instance where it refused to start, then suddenly started without any hesitation on about the fourth or fifth attempt.

I think something must be "sticking" for want of a better word, but as I've not yet managed to have the problem whilst the car is on my drive ( and an assistant to hand) I have been unable to make any measurements that are helpful.

The fact that it usually starts and then dies suggests that the fuel line must contain fuel under pressure - but that the fuel pump is not running and so the pressure falls quickly. If the fuel regulator is stuck, it must be stuck closed so that is not the issue ?The fuel pump obviously functions OK, in general, because the car runs OK if it runs at all. The manual circuit diagram (such as it is !) seems to show 2 supplies from the ECU to the pump, and the Haynes manual tells me that the pump will run for a couple of seconds to pressurize the line for starting, and then stop. So, how is the pump controlled by the ECU? What inputs are there to cause the pump to run(or not!), and specifically is there anything in the engine bay that might be affected by temperature.

I don't view the prospect of grovelling about beneath the vehicle to get at the fuel pump itself with a great deal of relish so if anyone can help it would be greatly appreciated

Thanks in advance

John