Despite the signage varying across the UK, some years ago I was chastised for using the Unclassified County Road designation.  So when  I stumbled across Unclassified COUNTRY Road, apart from wanting to sing John Denver, I thought I would change it to a more conventional tag.
This action seem to be supported in: https://osm.mathmos.net/prow/designation.html
If thats the wrong stance, then I would really appreciate a clear Wiki page on how we should tag these "ORPA's" (as the OS call them).
Im sure the designation is not supposed to be whats written on each sign and dependant on which neck of the woods you live in ?
Cheers.