Diagnosing Arotherm+ 5 & Radiators in Scotland

No, you won’t save any electricity this way. Instead of being on e.g. half the time and consuming electricity, the heatpump would be on all the time and consume energy.

It’s more likely a replacement of the sensors. I have a very detailed writeup here on what the (potentially multiple) issues are: Vaillant inbuilt monitoring vs MID meters - #97 by Andre_K