How to turn off Polypipe underfloor heating

[Betterthing]

Im house sitting for a friend & the heating is too high. How do I turn it off?

We have this and there is a thermostat on the wall which controls it. Looks like a little white box.

Thank you! Found it. Any idea which setting it is, please?

Just press the down arrow to reduce the temperature then the tick to select it.