It started after I flushed out the cooling system and put in 2 litres of Antifreeze because the previous Owner was from Auckland which does not get the hard frosts and icey conditions that a Winter near the mountains I work exposes you to.
First signs of a problem after taking it up to 1600m above sea level was a overflow of Green liquid which made my hart stop as I thought the LHM life blood was leaking out the Octopus
It was not but antifreeze overflowing 
When I got it home I noticed that from cold the lower corners of the Radiator were leaking this disappeared after the heat expanded the joints. Whats strange is the problem cured itself in a few days probably silting up? But I did start getting the low level light flashing on! This became annoying as most of the time it was a false alarm.
Replaced the switch which was badly corroded also put in some Rad Leak!
Now this is the part thats bugging me! Sometimes the water level after a long Journey 150 miles the coolant level is fine but if I kick in the Air Conditioning even for a short time then I lose water somewhere?
Checked the Radiator for cool spots and could find nothing.
The local garage said to me it could be signs of early Head Gasket failure
I hope not been there before and thats the death nail.after thoughtCould the Thermostat be clogged or faulty?
I am taking a monster gamble puting that stuff, its not like the UK type Holts stuff. Seems to be a bit thinner in quality.
I currently deal with Gary Keith Motors in Hamilton NZ, Its a three hour drive to talk to someone up there so most of my diagnostics is done myself.
as i think about this some of the hilss I would be going up are pretty step. Considering it mostly up from Sea Level to 1000m over 90km I might give this idea a miss.