"Dan Starkey (in-universe)" is a title based upon conjecture.
Check the behind the scenes section, the revision history and discussion page for additional comments on this article's title.
An unnamed man demonstrated Strax's advice about watching The Day of the Doctor in 3D. The man developed a mild headache after wearing a pair of glasses, then rubbed his eyes whilst muttering "what was the point in this exactly?" The man also wore a t-shirt with "reverse the polarity" written on the front. (NOTVALID: Strax Saves the Day)
Behind the scenes
While he was left unnamed in Strax Saves the Day, it was pretty self-evident that Dan Starkey played himself in the respective scene.