My heater matrix went earlier in the year (water in passenger footwell etc) but managed to plug it with some Radweld. However it's just gone again and I'm aware it's a dash out job to replace it (Very expensive!).I've heard of a product call K-seal,has anyone tried it? I now have the classic steamy windows. Does anyone know of or can recommend anything better than radweld to plug the leak,otherwise not really economically viable to spend a fortune on a 2000 1.0E Probably cheaper to part ex!