I tried to wind down my driver's door window the other day when it was frozen and I heard a snap. Now it doesn't wind down. When I removed the door panel today I saw that the steel cable for the mechanism has snapped (rusted!). Does anyone have any experience of changing this mechanism? Is it a readily available part. It looks quite tricky to fit and the Haynes manual doesn't give a lot of detailed info. Any help would be much appreciated.