Board Thread:Questions and Answers/@comment-71.68.238.251-20151007071932/@comment-25431873-20161207234418

Nah, Word of Jim:

Q: Is the original Merlin still alive? A: Kind of… life… death… it’s kind of a squishy line in the Dresdenverse.

Besides that, the original Merlin is older than the modern British accent. I would actually expect him to speak ye olde Englishe.