I took a quick look at taginfo and the tag you used, while logical, shows zero usage before which means its unlikely to ever get captured by any downstream tool. 

See here

https://taginfo.openstreetmap.org/search?q=heritage%3Alocal%3D*

I initially adjusted the tagging to historic but that doesn't strictly apply here either. Upon review I think the only suitable tagging is the original place=locality based on the description of that tag here

https://wiki.openstreetmap.org/wiki/Tag:place%3Dlocality. 

In summary, its back the way it started but hey, we all learned something today :)

Closing the note on the basis there is nothing else to be done with this, feel free to reopen if I've missed something