W213 Loose Driveshafts?

[Boobonman]

Bit of a weird one, I've got a 2017 E220d saloon with just over 140k on it. It had a faint clonking noise coming from the rear over poor surfaces, and it sounded to me like worn top mounts or shocks or something. I got my trusty mechanic to have a look at it while it was up in the air and he said all the suspension looks good with no play, but there is lateral movement in the driveshafts. This only manifests as a faint clonking, on a smooth road it is whisper quiet. Any ideas? Can I get them shimmed or something?