To be honest these showers are a known problem, it requires a new cartridge as washers etc can not be obtained as it is a sealed part! Retails at £105 for the cartridge alone to solve your problem!
I replaced 2 cartridges on my OLD Gainsborough (which uses an Aqualisa cartridge!) and got fed up of the £105 each time so I ripped it out and put in a Bristan... no problems with this shower in 4 years!!
Shazza, February 2010
