Just had my bike back after I had a few jobs done by a proper Yamaha mechanic (stuff beyond my limited capabilities).
#A.I.S. Removal: removed the A.I.S. system entirely rather than just clamping off the hose as before. the bike still pops and bangs a bit, but nothing like the shotgun sound of before.
#Clutch and Primary Drive Nut: the clutch cover was removed and the clutch plates checked over and new heavy duty springs were installed. The primary drive nut was also checked (as some reports of these working loose over time). Mine was beginning to work loose, so has been replaced, torqued and lock-tited in place. Also, new chain and sprockets.
#Full service: fluids and filters changed; valves checked and re-greasing of rear suspension and swing-arm.
#"Rattle": an annoying rattle that appeared somewhere around the headstock at around 3000-3500 revs in lower gears has gone!! Happy days.
So, the bike is pretty much good to go. I'll try and clean it and put on some ACF-50 before I go; but time is getting very short now.