Thanks for the advice, but I'm a bit of a novice on this. One do I need to turn off the radiator before I start taking the thermostatic valve off? An two is there a particular tool I need to take the head off as I can't just pull it off & am not sure which bit to unscrew! Sorry!

Pete, October 2008

sorry for delay i was searching for a picture to help http://www.gdplumbheat.co.uk/USERIMAGES/radvalve.jpg
this is prob not the same valve but there pretty much all the same but should help. below the arrow pointing to the numbers you will see a nut which is attached to the top of the valve body Screw it anti clock wise. in rare occasions you can turn it with your hand but if not use maybe vice grips or some form of pliers anything you can grab a hold of it with. when you get it off try to push the silver pin up and down to free it . sorry if im quite bad at explaining lol i will be here for the next half hour

paul, October 2008