I read parts of Geo's dissertation on the web, and am stunned she ever managed to get her Phd. It really made me lose respect for the University she got it from (Edinburgh, yes?) and shows how much the Phd process can be a crapshoot, based on who your advisor is.
While her thesis did incorporate some authentic examples of spiritual and visionary experiences from old manuscript sources (as opposed to, oh, Llewellyn or Capall Bann books), I just could not support that same old homogenization of "every sort of spiritual vision equals... shamanism." It's just so offensive to the diverse cultures. The parts I read were like, "Vision of birds in Old Irish tale, Vision of birds in Andean culture, ergo, same system, both shamanic." Gak.
I saw her on some Discovery channel program recently, waving a sword around and talking about dragons and claiming to be descended from King Arthur or somesuch. Oh dear. Can't say she came off too well. I've mostly avoided her. I know some people who knew her before she got started on her shameonick gig - they were in the same Harner class with her in New York City. Heh. Yup, like so many others, she took some Harner classes then pasted some Celtic lore into his system here and there. Nope, doesn't make it any more Celtic than the Wiccans who've been doing the same deal.