Actor Allusion: Cole Hawlings is Really 700 Years Old, possesses supernatural Powers and a Box that seems to be bigger on the inside, at least occasionally. This Box may also be used for Time Travel. The fact that The Second Doctor is recognizable under all that beard should surprise no-one.
Big-Lipped Alligator Moment: The scene with Kay and Herne the Hunter, in which they change into various types of animals and are chased by larger, predatory animals. The animation is quite nice, but it has no connection to anything that comes before or after, and does not advance the plot in any way.
Also, for all the buildup and pomp it is given, the Posset ends up being of no significance at all. Not quite as OTT as many examples but still qualifies on the total and utter irrelevance it has to the rest of the story.