Apologies. I thought I had been clear:
Replace fridge air sensor: Miele now send out an evaporator sensor to replace this, it seems. Whilst waiting for sensor to arrive we switched the fridge part off. The freezer maintained the set temperature very well.
In other words when you ask for a replacement sensor for the fridge, Miele recommended replacereplacement put an evaporator sensor in. The instructions are quite clear when you receive the package and when I spoke to the helpline.
You take the AIR sensor out and put a new sensor in which lies against the back panel of the fridge. There is a new replacement cover to hold it in place.