A quick though about roads signed as Quiet Lanes before I start the weekend...
You could add note="Quiet Lane" and/or something like designation=quiet_lane (but this could conflict with PRoW tagging) or the undocumented traffic_intervention=quiet_lane (tag used for some school streets and LTNs). That way, it's clear to other mappers why it's been tagged as a highway=living_street.

Have a good weekend.