turn the cold water off, turn the hot tap on to take the presure away. at the back there is a silver bar that moves, you need to be at the right hand end off it, lossen screw in the midell od bar and take out, at the right hand end of the barr you will see about 6 screws in a brass plate lossen them there might be a bit water, lift off brass bit and there is you rubber that has gone, take it out fitt you new bitt, but back together, turn water on and see what happens, the pin on the right should now come out move the silver arm so it make with a switch on the left hand side and you get hot water.
Befor you start all this turn on the hot tap and see iff the arem moves, if not you can move it by hand to make the switch and see if you get hot water.
erj
March 2010