Well, there's already been an encouraging comment - I suppose you could call it an endorsement - on The Grail: Relic of an Ancient Religion from the all-round Arthurian expert John Matthews:
"A brisk rattle through the well-worn paths of the Grail and King Arthur. Some challenging new theories, applied with a kind of relish reminiscent of Robert Graves, make this a fascinating book."
I'd call that praise. And now, this new review has just been published on the Radical Goddess Thealogy blog.
Definitely worth a read!