Went to a customer with a failed multipoint lock on their UPVC door today. The handles would only move downwards about half an inch so the door couldn't be opened. After opening the door and removing the lock mechanism the reason the handles couldn't move was because a small part inside the gearbox had broken and was jamming the mechanism. The part itself couldn't be repaired, and the manufacturers don't sell them as spares, nor do they supply the gearboxes as spares so a complete new lock mechanism had to be fitted due to a part costing a few pence breaking. Seems a bit stupid but I suppose it keeps the profit margin up.