I've found a solution. It could need a new thermostat, or the thermostat just could be faulty. I found this link
http://cgi.ebay.co.uk/Hotpoint-Creda-Dryer-Thermostat-REPAIR-NO-PARTS-REQ-/140378759750 and followed his instructions and it worked. A pound well spent!
Nic
March 2010