Leaking Shower Valve

[MrGatch]

I have a leak coming from the bath/shower/off switch on the attached shower valve.

The leak is coming from what looks like a rubber washer behind a brass retaining clip.

I've not removed the retaining clip as if I make the leak worse I won't be able to switch the water back on.

Any ideas with this one? Is it likely simply a new rubber washer, new cartridge?

Apologies, I don't know the model of the shower, although it is about 15 years old.

 

[MrGatch]

Anyone able to help with this?

 

[Ben-gee]

That is the flow cartridge. It is likely to be a ceramic disc mechanism, could be grit caught between the discs so it never shuts off properly- this is then leaking up the gland.
I would remove the cartridge, photograph measure and look for identifying numbers.
Then reassemble greasing up or replacing any o-rings in the spindle. Then try to find a replacement cartridge using what you found in removal.