Gwilym,
I'm nor a Celt in any shape, size or form, but I have a huge collection of Dragons, I sit here with at least 6 surrounding me at my computer.
I agree, the backing plate make this piece, it's almost as if the dragon was within it rocky home or backed against a rocky outcrop of the cliffs it lives within. And having walked many of the classic distance and mountain walks in Wales I can see the feeling you are trying to impart by use of such a texture.
If this does not may your grandson want to revisit the hills and valleys, nothing will.