My shower started leaking at the shower head recently and it's now progressed to the main shower control body, from between the control knob and the wall plate (I think). Can't work out how to take it apart, let alone what to do! It seems to get worse after I've used the taps in the kichen (the shower is linked to a combi boiler). Any advice would be greatly appreciated. Many thanks.
It was the exposed valve and I've managed to remove everything till the adjustable temperature stop (just before the first seal, as per the diagram you mentioned) where the 4 screws holding the cover in place are impossible to unscrew. I've tried WD40 and in desperation used my drill in reverse (not a good idea!!) to try and free them but to no avail and I've now destroyed the groves of the screws and no screwdrivers seem to fit. At this stage what can I do? Can't use pliers as screws are surrounded by plastic rim of the cover? Is my only option is to replace the whole unit?