When I (an American) first saw Peter Davison's first story as the Doctor, the name of the place where he is "supposed" to recuperate from his regeneration, "Castrovalva" just seemed to me to be another made-up science fiction name. Only recently, did I learn that it is the name of an actual Italian mountain village in the Abruzzi.
The real village is quite picturesque.
And M. C. Escher did a lithograph of it in 1930, while his style was still developing.
Thematically, the connection to Escher is important, since the Castrovalva of the story turns out to be a topologically distorted construct prepared by the Master in order to give the newly regenerated Doctor trouble.
This storyline ties in with two of the major related themes of Escher's later work—impossible figures and recursion.
Was the name "Castrovalva" well enough known in Britain at the time the episode was made that a significant number of viewers would have caught the reference? Knowledge of the M. C. Escher connection would have foreshadowed things to come in the plot.
If the name were more commonly known, that would explain another minor problem with the plot, which confused me the very first time I saw the story. When Tegan gets the information about where the Doctor should recuperate from the TARDIS's (fake) documentation, there is nothing in the script that indicates that the "dwellings of simplicity" they are heading for should be a mountain settlement. If anything, the dialogue suggests that Castrovalva may be the name of a planet, not a village. (Nyssa says: "The data bank is certain it's the best place to recuperate. It's in Andromeda. A small planet of the Phylox series.") So when Tegan and Nyssa reach the rock upon which Castrovalva is built, Tegan's certainty that they have found the right spot seems to come entirely out of the blue.
I assumed that this was either a product of poor writing, or some relevant details must have been cut from the final script. However, the whole sequence would make a lot more sense if some familiarity with the real Castrovalva was to be assumed.