I have a Candy fridge freezer (around 12 years old). The freezer compartment is working fine (-20 deg C), but the fridge compartment will not cool down (generally sitting between 5-10 deg C, with the thermostat setting above the door set at "5").

I originally found that the evaporator was badly iced up, so I removed the freezer back panel and fully defrosted the unit over a couple of days. However, even after doing this, I had the same problem.

From reading about similar problems, I understand that cold air from the freezer is ducted around the fridge compartment to cool it. I wondered if there is a problem with the cold air not being circulated correctly (e.g. blocked ducting) but I can't work out how the air is routed from the freezer to the fridge unit. When I removed the freezer internal panel, I could not see any obvious route for cold air to be ducted around the fridge compartment. The
freezer fan is working correctly.

Can anyone suggest what the cause of this problem might be, and if I do have an air circulation problem, where should I be looking for a blockage, please?
Thanks