Here we go guys, ATD on, timed up, back together, started first kick!!! Did sound slightly different on exhaust note - not bad, just different. Did spit through the exhaust a couple of times, but then seemed to clear. Tickover was slower than before, but she revved out well. Will leave overnight to see how much of the fibre teeth drops into the gauze and will clear. Put new springs on the bobweights, don't know if they are stronger than the originals, but that may account for something.
Screwed the centre nut on very, very carefully with timing buzzer still attached to the c/b to listen for movement. Then, holding it steady on the long maggie bolt at c/b end, nipped it up a bit more. Then got a screwdriver behind one of the bobweight posts to hold it steady for final tightening. Don't really want to load the fibre gear against the pinion even when the taper is sufficiently engaged.
It's now one of those confidence things. Do I attempt to go for a longish run or stay local for a little while. I told the recovery people that it was a timing issue and, because they don't recover for the same problem, I'd have to make up a tale if I needed recovery again. Fortunately, people have no clue with these bikes, so you can tell them whatever. I was asked when arranging recovery if it could be fixed at the roadside? I said there was no chance!