That's so great :D I've been to those too :D Cornwall holds special mystique to me, as do many parts of Wales. There's a King Arthur museum in Bude, too, which was informative. Unfortunately the Museum of Witchcraft also in the area had been closed by the disastrous floods that had Cornwall just a week before I last visited the area. It's open again but I haven't been to Cornwall for several years and I really miss it.

I admit I haven't read Mists of Avalon which I know is a major source for Morgana-fic. I'll look out for Cornwell in the second hand stores as that seems interesting and I'll see if my local library has a copy of the Tolkien Green Knight, thanks for the rec :D

I'm coming at the myths from a revivalist neo-pagan, and feminist lens; a lot of my current thoughts have been shaped by authors like John Matthews and Caitlin Matthews who translate and/or adapt Irish mythology, write about paganism, the Celtic Traditions, the Arthurian Traditions, and the legends of Arthur. Their Arthurian Tarot has The Green Knight as the Devil, appearing at midwinter and that image was my primary reason for future-Morgana to specify 'One midwinter...'
You can see the card here; my deck is a later imprint and has a nicer light border rather than the black but the main image is the same.