Hotpoint RLA64 getting too cold.

The thermostat capillary on a Hotpoint RLA64 (and possibly RLA80) is inserted into a tube. The tube becomes detached from the cooling element and so does not sense that the fridge has reached the desired temperature. It then carries on cooling resulting in ice build-up and freezing of goods.
As you cannot remove the top or back of the fridge, you cannot fix the capillary tube back into position. What you can do however, AFTER ISOLATING THE FRIDGE FROM THE MAINS SUPPLY, is to drill a small hole adjacent to the thermostat capillary tube and another in the roof of the fridge next to the interior light and pass the thermostat capillary INTO the fridge cabinet. Use tape to attach the capillary across the roof of the fridge and down the centre of the rear wall curling the last 50mm or so back up towards the top of the fridge. As long as you have dried the wall of the fridge and stuck the capillary securely in place, your fridge should now work correctly when powered up.
Only tackle this job if you are confident and ALWAYS ISOLATE the mains supply.