Beko AS920S American style double door fridge freezer faulty

Went out to one of these yesterday.
Customer told me that it knocks off and defrosts everything.
I took the back wall off in the freezer as there isnt much in the fridge because its a blown air unit.
I checked the defrost element which was ok, there is what I think could be a cut-out that shares the same plug as the defrost heater element and that was closed circuit. There is a sensor that is attached to the evaporator cover that seems ok, but not sure of the correct readings, and there is a sensor with gray wires that seems to be foamed into the back wall of the freezer. I assume this is the evaporator sensor.
While I was testing the element etc, I had the unit unplugged from the mains (as you do) and when I re-connected it, the display came up it nothing but a number 8…
Unplugged it, left it 5 mins then it came up with a number 4.
unplugged it, left it 5 mins again then display came back on but the unit didnt run. Spooky stuff. I think there is poss something electronic at fault here but this is the first time I have looked at one of these. I suggested they call Beko as it’s only 15 months old but I also told them I would put a message on here to see what i could find out..
Many thanks guys..
Rob.