Talking about winter weather with my youngest daughter this morning as she drove me to pick up a hire car (looong story) I bored her again with my tale of being down in Greenford near London back in the early 80's when temperatures dropped to an all time record low in the Thames basin. I think it was -17C, but my memory could be letting me down on the exact number? My car at the time wouldn't start as the oil in the sump had turned to icy sludge...