I've always been sceptical about woad Branwen, its a difficult dye to extract and how come they managed to grow it up in the wilds of Scotland as well?..
Ovid called us 'virides Brittannos' and for Pliny 'glastum' is the name, and apparently you can get blue, black or green from the dye, I'd like to know how they reduced all these dyes into a pigment form to use....
Always used to think that Glastonbury was so called because of the woad grown round there (woad likes growing on acidic peat and theres plenty around Glastonbury ).. but one of the stories goes that it was a 'Glasteing', a monk from the North chasing a sow to Glastonbury and he found her suckling her piglets under an apple tree next to the old church and he settled there.....