general warmup procedure for my fiesta diesel rotbox

picture the situation

its 3am on a cold wet and windy morning, the temperature is 5 celcius and there is a nip in the air.
the key is inserted, the engine starts, i slowly reverse down the driveway onto the road.
once on the road, first gear is engaged and off i drive upto the speed limit, holding it in 1st gear as long as i can - why? because the fooking heaters are still blowing cold, but by the time i get to the end of the street, 800 yards away, they are blowing warm