"Y Draig Dderw peers out of the trees onto the A5 near Tregarth ". This could be the real deal. In Spain the horned serpent is next to 2 pillars with a tree, on a Celtic vase. arcobriga celtic vase - Google Search: As Níðhǫggr of Yggdrasil was a tree-snake and German Oak of Donar was similar , and oaks were druidic, then the ram-horned snake of the continent was likely known in Britain. Camulos of Colchester was ram-horned. Maybe Y Ddraig was linked with oaks.