In my D1, in the summer, with no stat 145-150F. 160F stat tried, not much heat. 180F stat seems to be a good spot. Older Rover manuals had 82C stat for the V8 (and that is fully open).

If you have to run a colder and colder stat, you may want to consider other cooling system issues like cracked block, HG, bad fan clutch, multiple rows of radiator full of gunk, etc.

Owners don't usually report increased mpg in winter. Here is what the RAVE has to say about the temp in a D2, when the coolant temp sensor fails and a backup sensor method is used:

Should the sensor fail the ECM has a back up strategy that uses a changing default value during warm up based on
the signal from the inlet air temperature sensor. When the strategy default value reaches 60 °C (140 °F), the ECM
implements a fixed default value of 85 °C (185 °F). It will also illuminate the MIL.

I would take that to mean that the computer "thinks" 185F is a good spot.

 

Thanks, Savannah! I appreciate the info. Sounds like an ultra gauge is in my future.
BTW, I was stationed in Savannah while in the USCG, at the airstation at Hunter Army airfield. Savannah is beautiful place!

 

Pix of a UG in a D2 with a 180F Land Rover (not Motobad) stat.

When you are on the water, the approach of an USCG chopper is a welcome sight.