Candy CP2411F/9K fridge freezing up

Customer reported icing up behind the veg boxes and at the top r/h corner.
She defrosted it for 48 hours, then said the fridge wasn’t getting cold, so I went round and fitted a new control module.
Now it’s back to the original problem of icing up – (she apparently didn’t give it enough time for the fridge to get cold after defrosting it, it seems), so the new module didn’t make a difference.

Is the fridge temp sensor probe 97041867 easy to replace on this model, or is it an excavation and patch-over job?

Thanks in advance,
Pigpen.