Leaking shower from the on/off knob

[Mikeyb7]

Hi,

We have a leak from the on/off knob of our shower, I've tried to show where the leak is coming from in the pic below.

Am I right in thinking I can change the cartridge to resolve this? Is there a way to find out which cartridge I need before removing this one?

Many thanks!

 

[jj4091]

Try asking here https://www.showerdoc.com/identify-my-shower