Redring TR27T Immersion Heater - Thermostat?

[Vegable]

An elderly neighbour has asked me to look at her water heating as she thinks she's using too much electricity.
She has a Redring TR27T Immersion heater controlled by a Horstman Economy7 Quartz Control Unit.
Looking in the Immersion Heater top-cap, there appears to be no thermostat. There's lots of wires and looking at past discussion on this board it appears that this has a double heater, one heater element for the full tank, and another element for boosting.
The system works OK and switches on and off at the set times, and the water temperature is hot to very hot - back-of-hand measuring only!
I've looked inside the Horstman control unit and there doesn't seem to be anything inside that vaguely looks like a thermostat/heat setting.
I assume there must be a controllable thermostat somewhere, can someone advise me please
Mike

 

[seco services]

give us some

of the immersions.

 

[Vegable]

Thanks for your reply. I went back this morning to photograph it all and in moving wires around to get a clear picture the centre ones moved. On closer investigation they also slid upwards too. After disconnecting it and pulling, up came the thermostat, positioned right in the centre between the two elements.
I've not seen one like it before, only about 3" (75mm) long with the temperature adjustment halfway down the tube.
Anyway, I've turned down the setting and put everything back and we'll see how it goes.
Thanks for your interest
Mike

 

[pgeday]

Looking for that same thermostat, can it still be found?