While you wait for answers, we may have found some information which could help you.
Click here for Thorn Olympic Boilerunable to light pilot on thorn m44/54b boiler?
thorn m44 boiler fault?
thorn back boiler housewarmer s?
thermocouple?
thorn apollo boiler no gas coming through ?
Location of pilot light Thorn Housewarmer Super back boiler?