Focus hot start problem

[smithma0]

Morning.
Have a problem with my 2000 petrol Focus. This has happened twice now - after driving the car and it getting warm, then leaving for a short time (<5 mins), it refuses to start afterwards. The engine is not catching at all. If you then leave the car for 5 mins it will start first turn of the key.
I'm guessing this is a sensor/electrical issue??

Thanks for any help!