Ive got a bit of a drone from the back. I think its the tyres too. Jules

There is a section devoted to the FL2 Driveline, including descriptions of noises, in the Repair Manual starting at page 300.

It has section Headings like, Gear Howl, Bearing Whine, Chuckle, Knock, Clunk, Rumble,
AND a Symptom Chart. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 77k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)