thanks folks, the car doesnt get used much as I bought it for doing track days so will take me ages to actually cover a few hundred miles.
I take it I can just add normal water adding some rad flush or dishwasher tablet and run it with the cap off the expansion tank at fast idle before flushing again and do this a few of times before filling it properly?
I think I will try the rad flush approach first followed by a couple of runs with dishwasher tab and see how it goes.
Whats the volume of coolant required, is it 2litres water, 2 litres coolant for a 50/50mix?