Hi there, Rite ive had the coolant system flushed and a new rad cap and no problems since (fingers crossed)! Im going to monitor it closely and make sure its sorted but all good so far!! Also in reference to people with same problem i took my car to a garage and he flushed the system twice through and filled it rite up with new coolant for £25 quid which i didnt think was bad and definanlty worth doing!