2014 Stelvio whine from rear.. (not the missus)

Hello, I have a 2014 Stelvio NTX which I have owned for six months or so. I have noticed a low whine coming from behind me, so I assume it’s something to do with the final drive. It does not affect anything to do with the ride at all, apart from the noise ruining my enjoyment of the engine note! A few weeks ago I made a trip which involved trundling down the A1. At speed I noticed the whine increased to a more high pitched almost whistle type noise. When the bike is on the centre stand, I can spin the rear wheel with ease and it looks to stop naturally. I did change all the oils with the Guzzi recommended products when I first bought the bike. Could it be the CARC drive, or something else in between the engine and the back wheel? Is it possible to get reconditioned CARC units? Is it that difficult to whip it off and inspect it myself? I’m not shy of having a go at most things being a retired engineer. I just don’t want to start barking up the wrong tree immediately. Any suggestions please?..

Has it got chunky treaded tyres ? - they can often generate road hum, that increases in pitch, and volume with increased road speed.

I hope it is something simple, like that, and not anything ominous. :crossed_fingers: