HELP !! Ive changed my thermostat due to engine temp not even moving, now ive got a running temp of around 90degs, which l know is good. Ive no air locks either, thing is even when engine is up to temp ive got no hot or even warm air coming through my heater. It went quite warm ( not hot ) yesterday for a while then turned into freezing cold. Has anyone else had this problem, and resolved it??Thanks for any help.

If u changed ur thermostat, then u had to drain the coolant. My first thought is that u still need a half gallon of coolant in the system. BUT. u said u have no air in the system? Hmmm.
Did u test for air in the system WITH HEATER wide open?
NOT being sarcastic sir, but did u install the thermostat with the spring pointed towards the engine? This is the correct direction.
Other than AIR still in the system, & a NEW thermostat, l cannot guess. 90 degrees centigrade is indeed normal.

OH WAIT. one far-fetched long shot idea. ur cooling fan in front of the radiator will not shut off, thus OVERcooling ur water??? Ok, l am out of ideas now.

The 306 thermostat housing is exactly the same as the old 205. (TU series engines, 1987 -98). You could even ask ur friends or mechanic about the 205.