Trock as explained but Wikipedia is, "Time Lord rock (sometimes shortened to Trock) is a genre of geek rock music based on, and about, the Doctor Who television series. It was created in 2008 in the United Kingdom with the formation of Chameleon Circuit."
The BBC's digital Doctor Who 2016 Adventure Calendar.
Countdown Till Christmas Special Airs: 10 sleeps
Countdown Till This Whovian (probably) sees the Christmas Special: 11 sleeps