Hi bluemax.
coincidence as it that today my son came round to my house and he mentioned his engine was running cool, even after a good run over differing roads and hills he could only reach 74c.
So we set about fitting him the inline gates thermostat that I had already got fixed into the top hose, once fitted and we bleed the system he is now getting up to 91c before the thermostat opens and once opened he is getting a constant 87c, we will continue to monitor this over the next few days and see if it is fluctuating anymore than that. Arctic2