Daragh

Please find video links here: They're only short and the noise only evident at the end of videos

Hi all, 2016 A4 Avant Quattro S line. Ongoing high pitched rotational noise from rear of car over a certain speed (approx 15mph). Appears to be coming from rear left area. Been to main dealer who assure me it's not pads, discs, bearings etc. but they can't find a source. Still present when coasting in neutral. I've experimented with GoPro and will try to upload some videos now. Any help identifying would be greatly appreciated