I saw your post right after I finished this - you're right that it doesn't have the kind of high Gaiman mythos that I saw people worrying about. It's definitely Doctor Who. But the aesthetic and everything was what I was thinking of. Have you seen Neverwhere? The costume/set design for this episode and for Neverwhere feel so similar to me that I'm convinced Gaiman must have gotten really involved with the design staff on Doctor Who.