Hi K, thank you for your help so far.
I have checked the damper and have seen it work when turning the fridge thermostat down and back up again.
I noticed that when I removed the vent (part number 56547 on the diagram you sent me) at the front top of the fridge it is full of ice. Also when I opened the freezer door I noticed cold air started to come from the vent (I chipped a bit of the ice away) and when I closed the freezer door again it stopped. The fridge is still not cold though.
any ideas?
thank you