T120 Slipping Clutch Tip

I suspected it over the last few rides but today I confirmed it. The clutch was slipping (most dramatically when in 2nd at about 20mph, whack the throttle open and watch the tacho spin up to 6000 before grip was found and acceleration starts).
Phoned the dealer and he said to check the clutch lever pinch bolt as he has seen them 'tighten up' of late.
Slackened the nut off by a quarter turn and all now ok, with the added bonus that the clutch action is now 'light as new' again (something I hadn't noticed!!).