EdLoach
(Ed Loach)
2
Some of the county boundaries are in, if not all. They’re tagged in a variety of ways. Sometimes with boundary=administrative and an admin_level= (some number), and sometimes they have been done as part of a relation. Perhaps both.
The border between Essex and Suffolk is fairly clear on the river Stour here (the .-.-. rendered boundary):
http://www.openstreetmap.org/?lat=51.9458&lon=1.1928&zoom=12&layers=B000FFF
See also Key:boundary http://wiki.openstreetmap.org/wiki/Key:boundary
and Relation:boundary http://wiki.openstreetmap.org/wiki/Relation:boundary
I’m afraid I’ll have to leave it to somebody more knowledgable on how you would query the database to get just the relevant information though.
Ed
PS: I suspect the NPE layer was used in many cases. I used the NPE layer to denote the Essex districts based on the old parish boundaries, from some list of which parishes are in which district (perhaps wikipedia sourced). It may be that the parish boundaries have changed in places, so the district boundaries may well be wrong as you point out.