I've just been watching a couple of the other episodes (Shakespeare and Gridlock), and we also see the inside of the TARDIS doors then - maybe they were white once, but now they're a very dirty brown colour.
Which once again brings up the question - if the inside of the TARDIS we see in the trailer is the Doctor's, why has he cleaned the doors? It might sound a bit trivial, but it just doesn't seem right. He's had dirty doors for every other episode, why should he suddenly clean them?
There's a bit of strangeness for you - I'm pretty sure that on the front of the TARDIS doors, the poster says "Pull to open", right, yet both doors push open, don't they?
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As for the double episode mentioned, well, what can I say but "Wow!"? It brings up so many questions, which will probably be answered in the episode... ooooh! You'll remember the end of the Shakespeare episode, where the Doctor is chased out of the Globe by the guards after the Queen sees him, yes? Is it just me trying to make links, or would you say that the time period for the episode with the burlap doll looks like the right time period for the Doctor's run in with the Queen?