Doctor Who Natale Special - The successivo Doctor [Screencaps]

I'm Spanish and according to my calculations, is likely to start arriving summer episodes of the series 7 to Spain, dubbed into Spanish. And that gives me some doubts about the dubbing and translation of new episodes.

Translation of the names of the episodes and references and jokes più British.

Translate it o not?
In Spain, not all the names of Film and series are translated literally (The sound of Musica is in Spanish smiles and tears) so it makes me think if will be literal o not, when te translate names episodes.
In this sense, my doubts are mainly in two episodes, A town called Mercy...