Cheers guys, really does sound a fascinating place and looks an absolutely stunning setting to boot. Wherever you find Galician / CnR type carvings there’s always a few characteristics binding them together (apart from the design element) and it’s hard not linking the positions of these things to something prominent in the landscape, be it a mountain, river, valley etc.
Looking at the photos, you can certainly see why the mountain & pass may have drawn their attention, in a similar way the Cheviot grabbed hold of the carvers in Northumberland.