This is an old book-1989-so it does not reflect modern scholarship. I picked it up on a lark and claim no special expertise on the topic. That said, this read to me as highly, highly, highly speculative. I wouldn't say it goes as far as "Holy Blood, Holy Grail" in its tenuous conclusions but to connect Boudica and the Iceni revolt to a random bog body of uncertain carbon dating based upon a piece of burnt bread discovered in the digestive tract of the corpse is open to some reservations. The authors go so far as to declare they have determined the individual's name. Not what they decided an appropriate name would be but his actual name. A lot is predicated on that piece of bread connecting it to a Celtic Beltane rite where the random recipient of the one blackened section of a barley loaf was marked for sacrifice. Fifty pages later though, Lindow man has been endowed with such stupendous significance the authors must alter the ceremony to have him voluntarily select the burnt piece because his sacrifice is too important to be the result of the known, random ritual. There's a lot of reasoning of the type where if A is possible, then B is possible, then C is possible, therefore D is true.