G'day Paddy.
I have a bad habit of missing the most simple things. TT is right, throw a new set in first NGK B6HS or equivalent in your fav brand.
Pilot screw 1 1/2 turns out from seated. Get the bike to operating temp (15 minute ride), set idle then adjust the screw in till she falters then turn out (count the turns) till she falters. turn in to half way between the two. Then re-adjust the idle. This should be pretty close, you might find it needs no more than an 1/8 turn either way to get a clean transition onto the slide.
This may not be the way the "book" says but it works for me.
Cheers