Loafer has a BD3 engine I think.
Warming up takes a long time as the 3 litre lump is a heavy beast at 450kgs, plus gearbox...
I have had the same issues ( see 'Smaller Calorifier thread ) with it being slow to make a tank of hot water.
I fitted a heat exchanger system ( copyright of Smileypete of this parish) instead of using the Cal-coils, reduced the time to about an hour.
At the end of the day it's a tractor engine designed in the early 60's when having a tractor sat stationary in the yard running PTO machinery was still required, i.e. a cool running engine anyway...
Cheers Bill
P.S. and no my thermostat isn't a wrong un :0))
No disrespect to Mr Brooks, sorry if this sounds flippant, respect due Sir.