Hisense RQ689N4BD1 Fridge freezer – 4 door – Freezer not cold – help Please

Hi,

My fridge freezer is just out of warranty. The freezer – bottom right – is not cold at all. The control panel says -25 but wont even freeze ice cubes.

Bottom left is cold but not as cold as it should be.

I am quite handy but cant find how to get the evaporator panel off the back to check the temp sensor.

Any help with this would be greatly appreciated.

Hisense want to charge me £179 for a call out.