Leaking Thermostatic Shower mixer
 

My New Team Thermostatic Mixer Shower valve
(http://www.newteam.co.uk/projects/cn...ElemFormat=jpg)
100 series has started to leak again (dripping down from the water flow
control lever.

It had leaked before shortly after being installed and the fitter put a
pressure reduction valve after the water mains.

Nevertheless, even if I reduce the pressure right down, the mixer still
drips.

Does it look like I have to replace the cartridge, which I think costs
well over GBP100 for parts alone. Would it be easy to replace the
cartridge or any parts inside? Do I need any tools other than a
screwdriver and a pair of pliers?? I am inexperienced. Cheaper fix
would be good!