It is not difficult to see how the word Wicca would come from Hwicce.
Below are excerpts from Richard Coates on the origins of the word.
Also interesting is both the Hwicce and Dobunni have concepts of a cup or trunk/hutch, as well as being the “shine ones” or “excellent ones” or “the pure.” These are also Grail concepts and have ties to Pandora’s box.