discovered last nite when looking round the engine bay that the temperature sensor for the radiator was unplugged. the pins in the plug had corroded and so the plug dropped off. therefore the fan wasnt kicking in as the car was getting too warm and the engine was heatng up when idling. this i hope was the cause of the low oil pressure light coming on, because the engine and oil was so warm that the pressure dropped. hopefully will have problem sorted by the weekend