I have a 7 years old Zanussi fridge/freezer (one of the self-defrosting ones). Lately the fridge keeps defrosting and floods with water. There is a little hole in the bottom of the fridge where I think the water is meant to go but clearly this is not happening. Is it possible that this hole is blocked - there used to be a little pulley key thing there but it's gone now. Any ideas how to unblock the hole? Should the fridge be defrosting almost every day? I have checked the seal on the fridge door and it seems to be fine so I don't think that's the problem. Thanks in advance for any advice.