[Efendija]

Not exactly untranslated, the episode one subs were:

Spoiler:

...
-Is the capital there called "Kyoto," too?
-You've got some idea, right?
-I think "Kyoto" is a fine name for it.
-At least change the characters in the name.

And so the family moved to the city beyond the looking glass and vanished unnoticed.
^(here the narrator says kagami no miyako)


The new city was ruled over by Koto and the priest, and named the City of the Looking Glass.
...

After that however, it was referred to as "Looking Glass City" until the show's end (when the characters pronounce it as Kyoto).

Also, the episode descriptions do use "Looking Glass City" as a name a lot.

Discotek is doing the English BD/DVD release and I don't think they'll change the subs (if they didn't release it already, last I've read something about it was in March on their Facebook page).