How to repair this?

[Jon_moss]

Hi, I’ve got a mixer shower that leaks. I’ve stripped it back (see attached) expecting to find some sort of cartridge that I could then replace. But I’m lost, is the cartridge buried behind the tiles?

 

[Wayners]

Where is the temperature and flow control? You removed?

 

[Jon_moss]

I have all the parts, flow control is the top pipe, bottom pipe is temperature

 

[Burnerman]

Can you remove that knurled brass wheel- with the centre screw - to reveal the larger hexagon behind?
You could shift that with a deep drive socket, likely enough.
John

 

[Wayners]

Looks likely it's behind tile then.

Looks under bath or vanity if you have one for spare tiles