I did enjoy this book, although I felt he did labour the (essentially simple) point a bit much - but then I suppose he was trying to get a book out of it.
I was particularly pleased to find his confirmation of the site of the 'lost Druid sanctuary' of Medionemeton in Central Scotland as Bar Hill Roman fort, because it is exactly half-way along the Antonine Wall. This is something that was suggested back in the late 1970s by Harry Bell in 'Forgotten Footsteps', his research into the ley alignments of the area.
Grahame The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it - Terry Pratchett.