Unable to answer "What number or code identifies this stop?" – Monash Medical Centre (Bus Stop) – https://osm.org/node/10831185119 via StreetComplete 62.2:

this stop's information paper is gone, but the stop across the road has the number. They are the same stop for different directions. Stop number: 15882

Attached photo(s):
https://streetcomplete.app/p/329891.jpg