osmuser63783
I've taken a stab at this, as discussed yesterday:
https://www.openstreetmap.org/relation/15867809

The MP is a bit ugly, I hope this is the only place in Edinburgh where the block/terrace/named place is split.

Nominatim is happy:
https://nominatim.openstreetmap.org/ui/search.html?q=9+leopold+place

Compare the nonsensical / incorrect results below:
https://nominatim.openstreetmap.org/ui/search.html?q=1+leith+walk
https://nominatim.openstreetmap.org/ui/search.html?q=7+randolph+cliff