I have an old Ideal mexico slimline 2 CF55 boiler on which the pilot light won't stay on. i have sourced a thermocouple, as a local expert who could not come and see me because of his workload, said that is what he thought it would be. however i am nervous about changing this out as i cannot get the boil part out far enough to get to the underside of the boiler to access the thrmocoupleand naturally dont want to damage anything. can anyone give some advice on how to proceed? i would get someone in if only i could find someone.