User blog comment:Dragoon leGreat/The Euchdag?/@comment-4190137-20121002055137/@comment-4190137-20121002131849

The thing that looked like the Dochraid in the trailer could and probably is the Euchdag.

Maureen Carr and the Dochraid weren't credited in the BBC1 synopsis, unless they are saving it for a surprise... But it's the Dochraid so I doubt it.