Kibana United Kingdom Subdivision Region Map - Not matching all UK cities

I have used the "United Kingdom Subdivisions", the maps shows few cities but not all cities like Hull, Bristol, London..etc.

What could be the reason that these places are not showing in maps?

The UK subdivisions only include regions that have an ISO 3166-2 code. https://en.m.wikipedia.org/wiki/ISO_3166-2:GB