Well, since it is fantasy there's really no such thing as an anachronism possible. These things never happened, and thus something that's part of it can't be "out of time" -- it was never "in time" in the first place.
That being said, silly british accents don't make the language any closer to a "medieval" setting that so many people apparently strive for. To the degree that anything can be considered anachronistic, I'd say that's the most consistently glaring (though I will note that it bothers me not at all).
But, do whatever makes you feel good (as long as its legal, anyway). If you want to have crystal balls that work as the internet - go for it. It's not like someone can huff away from the table, saying, "real crystal balls never worked like that!" since there just aren't any real magic crystal balls.