All these cabinets, the position of the sensor varies and (I think) which is used where so most of the repairers just have the two often changing both to ensure they kill the problem.
To find them, you need to follow the wiring and dig them out, keep in mind that these were never intended to be replaced and this is a field mod in effect that is not in any way, shape or form offered with support for the general public to do it. So, Beko assumes that a pro repairer and not amateurs will do this, therefore, the chances of instructions are pretty much zero.
Just in the same way that Ford doesn’t offer step by step guides on how to repair their cars or modify them etc.
About as much as you can expect can be found here:
https://help.ukwhitegoods.co.uk/support/solutions/articles/6000093862-electronic-fridge-freezer-sensors
Beyond this I am afraid it’s purely down to the skill of the person repairing it with many of these units.
K.