I'm running a 1800 subaru in the rear with a rad at the front. The system seems to be deleloping a lot of pressure as the hoses are quite hard once the engine is hot! I don't think a head gasket is blown as there is no water in the oil and no steam exits the exhaust. I'm also sure that I've got all the air out of the system. The pressure is also less than the pressure cap blow off pressure, 0.9 bar. As i my other car is a diesel I'm not sure if this is normal?

It sounds OK, the system should be pressurised when hot. The water will expand due to the heat in the system.

You have an expansion/overflow tank? As the water heats up it expands into the tank, then returns to the system as it cools down.

Yes i have the Jap type system with a over pressure expansion tank. when the system cools it sucks back from the tank.

We'll be out on the road very soon so i guess that will be the acid test!!