header tank boiling over.
Hey Guy's , me again , great news, took bottom and top hose off rad , carefully removed all water till it dripped no more.
Next step was to flush Rad out which I've now done bottom to top as suggested , the **** that came out was no-ones business, black bits and old K-Seal copper particles.
I then refilled header tank with same stuff I drained out ( too expensive to waste good antifreeze/coolant ). carefully filling with heater on hot , as to bleed properly.
I poured this through a pair of the wife's old tights as not to contaminate it again, guess what???
Running like a dream now, the bottom hose is now getting very warm as well and my header tank isn't boiling over, so after all that money , water pump, stat, stat switch, etc , etc. it was a blocked radiator, There's a lesson to be learned from these few lines.
Many thanks to all who contributed to helping me.