Bit of a strange one... My mum's got a 53 plate 1.8 tdci focus. If you use the car but it doesn't get warm (journey of 0.5 miles, stalling it pulling off drive etc), the car will not start again. It will turn over and over and sound like its trying to catch but will not start at all. If you return to it some time later it will (usually) start. It normally starts ok but its just when its been started and turned off without getting warm. Car is regularly serviced and recently had new plugs but hasn't made a difference. Any help/advice will be appreciated.