I'm pretty sure there is (or was) a street sign that showed the longer version. I can't tell from Bing or Mapillary imagery unfortunately.

https://www.mapillary.com/app/?pKey=592400701915373&focus=photo&lat=54.1685669&lng=-4.729383&z=17&x=0.16791542171218904&y=0.5349919565261344&zoom=2.2633587786259524

I've added a note to remind me to check next time I'm in the area https://www.openstreetmap.org/note/4977365