Thanks again for all the replies. I have to admit I have not been back to work on the car for the last couple of weeks due other commitments. I pulled out the radiator and gave it a good flushing (which did expel quite a bit of rusty looking stuff) and also removed the thermostat which I will test in boiling water. next step is to remove all other water hoses as it seems to me to be like a blockage somewhere as it seems to pump the pump dry. Some of the hoses on the inlet side of the engine(that feed to the oil sandwich plate or whatever it is called) look to be pretty hard to get to but like I say I haven't really tried yet. If I don't find anything I guess I will have to remove the pump to have a look at that. David