Shower mixer model / supplier

[Trackerleigh]

Hi, I am trying to identify this thermostatic mixer valve to source a service kit. The water on off control seems to be getting stiffer, it's difficult for someone with limited hand grip. Photos of the valve attached. I can provide a photo of the control knobs fitted if that helps.
Thanks

 

[Trackerleigh]

This is the mixer fully assembled. When I removed the outer temperature control knob there was a circlip loose which also seemed to be deformed or an odd shape. Since it's a power shower it's either on or off so any difficulty turning it off is pretty wasteful of water and energy.

 

[rpm]

Send photos to theshowerdoc.