Dear Tony,
I hope you don't mind me writing to you. I'm currently reading your book, 'The Killing Way' which was recommended to me by our friend here in Tucson, Susan Cummings Miller, the mystery writer. I'm enjoying the book tremendously, especially as I'm a Welshman married to an American.
However, I felt I had to write to you to point out (if it hasn't already been pointed out) that the map in the book is way out as far as Carmarthen (Moridunum) is concerned. Your map has it situated at Newport in Gwent, when it's actually about 80 miles to the west. There were, of course many Roman settlements and forts in and around Newport, but Moridunum is not one of them.
Carmarthen is a great place to put the birthplace of Merlin, and you're right that the Demetre was the tribe in that area, but the Silures would have been the power in force in the Newport area.
Anyhow, I'm sure you know all this and the map point is a misprint, but I thought I'd point it out and take the opportunity to wish you all the best with the book and future ones in the series.
Best wishes,
Tony Blackwell.