thought id give it a go today and try sort my lumpy idle.
I know the problem and the cure

took the lead cover off to reveal strangely enough the lead , went to number 5 pulled it out and its covered ney DRENCHED in oil ("O" rings ) any way cleaned the lead as best i could, tried to extract the plug only to find I have the WRONG size socket BUGER BUGER BUGER .
So its still lumpy

But i did leave the cover plate off. (forward thinking) pmsl