A new prequel has been released today for The Snowmen - titled Madame Vastra Investigates. As the first prequel (The Great Detective) had snow on the ground, and this has snow first starting to fall, is it the prequel to the first prequel? It has also been announced that on Christmas Day, viewers will be able to see a new red button Vastra mini-sode - in which she investigates a bizarre murder. The murder, the conclusion of which, we see in today's new prequel? So, will that make it the prequel of the prequel of the prequel...?
I think I might have to go and lie down. Vastra seems to have picked up River Song's annoying habit of doing everything backwards.
It has also been announced that we are getting a new title sequence and substantial rearrangement of the theme music. (DWM did say that it was also getting a redesign from the January issue).
Here is the prequel of the prequel - but not the prequel of the prequel of the prequel...