Shower mixer parts advice please

[Jcfros]

i have a hidden shower mixer which has been intermittently playing up recently. Sometimes it does not give full pressure and sometimes it does, sometimes it is difficult to turn off as well. Unfortunately there is no manufacturers name visible on the unit anywhere that I can see - I can access the back of the unit through a panel but cannot see any manufacturers name. I’ve removed the control knob and think the problem could be the plastic inner knob which seems slightly worn on the inside where it fits over the knurled end of the control valve. can anyone advise if these are available as spare parts or if I’m barking up the wrong tree please?

 

[steadyon]

1. Looks like an Ideal Standard Trevi Therm. Send the picture to showerdoc.com and see if they can help.
2. If it is, they have a pinion and gear system to shut off the hot and cold. The gears can slip / get out of sync. which could cause the problems you set out.
3. The prices for spares are pretty steep.