They didn't have English accents in the 1959 movie. The early 60s Tower of London starring Vincent Price was set in England but had zero British accents.
"Learn from me, if not by my precepts, at least by my example, how dangerous is the acquirement of knowledge and how much happier that man is who believes his native town to be the world, than he who aspires to become greater than his nature will allow." Frankenstein