After repeated stripdowns, the only thing causing any stiction whatsoever was the fork seals.
I removed the upper seal 'grip spring' and put it in the lower springs position.
The top spring is much weaker than the lower one.
Still under trial, if/when I am satisfied that I have cured the harshness, I'll post a 'how to' in the relevant thread.
I'm still unsure as to why mine rides so harshly compared to others....
Phil