Have you ever been to Stonepitts Bridge? I have. It is an agricultural track, for tractors, with footpath permissions, not a narrow footway. You are not mapping to ground truth.

https://wiki.openstreetmap.org/wiki/Access_provisions_in_the_United_Kingdom

"Note: Rather than being influenced by the name of the access provision, tag the feature according to what you observe on the ground. For example a 'Public Footpath' that runs along the route of a farmer's track should be tagged as highway=track rather than highway=footway."