I am so chuffed with myself , I have just flushed through my system with G13 mix , so easy to do. I am an ex Royal Navy Articifer so quite handy , I hear this is a 250 pound job ! It took me 30 mins , I then put system on for leak test . If anyone is interested I could do a write up , it is the Alde 3010 system with the wee pump in header tank , the original blue coolant in it since build ! I suppose it will be similar for the new system 3020. Just come from the storage site now