Recently the fridge/freezer appears to stop/start working intermittently. When the appliance is not working it is accompanied by the green power light flicking on and off. Also when you open the fridge door the light flicks on and off constantly about 1 per second. After a while the power light glows constantly and all is working fine. I have noticed that if you press the fast freeze button the flashing lights flash much faster. An engineer came out about six months ago as the fridge wasn’t working but the freezer was. It turned out to be ice build up preventing the cold air from the freezer being blown up to the fridge. All has been well since, until now! Any help please.