Not seen one of these before, not that old. The freezer is not cold at all, evaporator is clear. The fridge is holding temp and the backwall had a small build up.
All I could find was a defrost heater reading 780ohm???? But there was a sensor in the freezer aswell which appeared fine. I have ordered a new PCB as ever thing else appeared ok.
You have freon lost….
In Indesit combo if you have just one little hole (less freon) freezer reach temperature but not also the refrigeration part. If otherwise you have an major leakage (freon lost) both parts F&R don’t go cold.. because at start when valve is switch for refrigeration freon goes also thrue freezer part.
Check also motor for loosing power( compression).
But question is why the valve doesn’t switch to freezer compartment? Did you hear at beginning of work (before motor start) switching valve working? If yes then perhaps you have clogged capillary.