hi folks i have a minor problem my fourtrak (thug) will not reach operating temp by that i mean the temp gauge will not pass go and the heater only pops out luke warm air

so far have done sniff test (ok)
pressure tested system (ok)
backflushed rad (ok)
temp test water (92c) OK
rad cap checked (ok)
no collasped hoses
fan working (ok)
no leaks , no screaming water pump , no white smoke , no oil in water can see water circulating

before i rip the stat out(jammed half way methinks) and condem the water pump to meet number 2 angle grinder has anyone else got any ideas

i mean it still goes like a train but it gets cold in the north of scotland and i am getting old