haha cheers
i did have a circulation problem but that was the water pump which has been replaced.
Now the basic symptoms are that the car takes a long time to heat up when standing stationary/ driven slowly but as soon as I drive on fast roads it cools right down. I can only think its the thermostat but ive only just replaced that so unless its a dodgy thermostat ive fitted i dont know what it is but as youve mentioned it might be the sender unit. There are no problems performance wise. Been offered £3000 for it though which is a good offer but need to get this fixed before I can sell it to anyone.