Hi, with the cold weather, and gunk all over the roads I have a couple of washer jet related questions! Heated Washer Jets: I've read two things about these, one says they come automatically below a certain temperature, the other says they come on with the rear windscreen heater (and another states the wing miror heaters should be selected). Which is it? Headlight washers: Do these spray everytime you spray the windscreen? One in ten times? Only when headlights are on? Cheers!