to be honest, when we filled the car up with water, all we did was put antifreeze in the little tank near the radiator, then add water from the hose until it was full up, ran the car for a little bit, topped it up, ran the car further, topped it up a bit more, and then all was fine.
Note that in between filling the car with water, the engine temperature was under the red, and fans were kicking in.
So I dunno, yesterday we took off the thermostat to check water was getting in, and there was no airlocks, but the engine still continued in the same way
cheers,
Paul