No, it's got a mixer box (for want of a better word) in the attic that's plugged into the mains.

There's a wireless dial that talks to that, and the water itself comes from the gas combi boiler, rather than electrically heated.

I think it was this one.

https://www.mirashowers.co.uk/showers/digital-showers/mira-mode-dual-shower-ceiling-fed-high-pressure-combi-boiler/

Quite a bit more expensive than a regular thermostatic mixer shower, but since I was having the whole bathroom done I figured why not spend a bit extra on some nicer stuff. The labour is still the most expensive part by far.