Buying a 2016 520d - anything to look out for?

[TheRingDing]

I am viewing a few 520d's this weekend with the hope of buying one.
All are 2016, some are better specced than others (harmon kardon, etc), and they are all sitting around 70,000 miles.
Is there anything specific I should be looking for? Any common defects that are easy to spot?

[danb79]

Service history; proof that the engines been looked after and maintained properly. Check for recalls (if it's had them or needs them) etc