I understand that cold weather normally affects the performance and economy of most, if not all, diesel engines. I've noticed in my SC 1.6TDi I get 52MPG when it's a warm day (7oC I class as warm at the moment!), and I get around 46-47MPG when it's cold (-0.5 --> 0.5 like today). Is there any way to keep the MPG up in cold weather, i.e. addictives? Or is it just something to live with?