Hi guys, I'm have trouble adjusting the temperature on my mum's shower head, how do I do it?

[annmarionryder]

The shower was far too hot for this Summer even on lowest setting. I've taken off the cap and screw which led to the heat dial coming off, and now I'm facing this toothy something, and not sure what to do next. I've tried researching it, but I cant find many similar shower heads and without the terminology I'm a bit lost. Can anyone suggest the next step? I'd greatly appreciate any help given.
Thanks,

 

[Jeff Handy]

Looks like more of the chrome trim has to come off, by unscrewing or twisting or pulling.
Then you will expose the cartridge underneath, which probably needs to be changed.

That valve does not look familiar to me, probably something European that we don’t get over here.

 

[breplum]

It is a "shower valve" though I think you folks call them "taps". Which is what beer flows from over here.
You may be able to reduce the temperature mix on your boiler (we mostly have "water heaters").
Modern shower valves over here in the U.S. have high temp. limit adjustments to prevent scalding.
It is not a fixt. sold here.