Some years back, I'd read of temperature fluctuations in the K. So I did some coolant temp testing on my own VVC MGF. I used a two channel digi thermometer that used K type thermocouples. I placed one thermocouple in to the top of the head, via the top hose. And the other in the bottom hose inlet to the pump.
I found the engine temperature climbed rapidly from cold. It went well over 100° C. Both thermocouples showed similar readings. Then as the stat (standard location) opens the bottom hose temperature plummeted down to 20° C. The top hose showed a similar drop, down to 30°C From then both thermocouples climbed rapidly again towards 100° before dropping sharply again, but not quite as low as it's initial drop. I'm sure that the cold coolant rushing in past the stat closed it again. This cycle of heating and cooling continues for some time. Each time the cycle repeated, the extremes reduced, until the temperature stabilised.
This cycling of temperature is the main reason the HG failed so early. The MGF with it's rear mounted engine and the hard worked Freelander engine, were the most likely K's to develop temperature related HGF.