We have sourced some county boundaries but they're not available on the Atlas front end yet. The GB local authorities are listed under pre-defined areas: https://regions.nbnatlas.org/#rt=Local+Authorities+GB.
We have a Non-Metropolitan Counties and Greater London (England) shape file uploaded that we could add to the Atlas and the Northern Ireland counties are already on the NBN Atlas NI: https://northernireland-regions.nbnatla … +Ireland). We would need to source a similar files for Wales and Scotland.
Records can be filtered using the 'Non-Metropolitan Counties and Greater London (England)' shape file but you have to tweak the url and know the name of the county. Here is the list of records on the NBN Atlas for Warwickshire:
https://records.nbnatlas.org/occurrence … 0County%22
If this is helpful, I can give you all the county names. We could add this as another filter option under Location but we would need to include Wales, Scotland and NI counties.
NBN Atlas Data Manager