Thermostat case too small for backbox

[jf93kf]

Hello all.

I'm replacing my thermostat with a temperature sensor casing. There are two issues with it:
1. The holes on the back of the new casing don't align with the two screws of the backbox.
2. The sensor casing seems slightly too small for the backbox/hole in the wall which means the edges would be a bit messy.

Does anyone have a suggestion for how to overcome this in a tidy way please?

 

[foxhole]

Might be able to fit blanking plated and then fit to that.

 

[jf93kf]

Oh that’s exactly what I’m after. Didn’t know that was what it was called. Thanks very much!

 

[pcaouolte]

If you get a PVC blanking plate like this: https://www.toolstation.com/pvc-blank-plate/p29677 they are easy to cut and drill without cracking or shattering. They are very thin so they don't have much strength but a thermostat doesn't usually need much support.