James Derrick
Hi,
After a ground survey, this is an access road to two cottages with a 'Road unsuitable for motor vehicles' GB:820 and 'Dead End' GB:816 sign. After the cottages the surface is gravel and earth through a gravel ford. It is a legally a BOAT so specialist 4x4 might make it through, but I'd prefer a tractor!
Highways have been downgraded to more realistic tagging - certainly not a tertiary.
Happy Mapping, 

James