The speech given by Group Captain Peter Townsend in this episode was actually a statement issued by Princess Margaret.
The "Balmoral Castle" in the series is actually filmed at Ardverikie estate, Highland, Scotland, UK. Ardverikie was the castle in the TV series "Monarch of the Glen" and in the movie "Salmon Fishing in Yemen".
Cecil Beaton (Mark Tandy), while prompting Her Majesty's poses, says: "Not moving, not breathing. Our very own goddess. Glorious Gloriana". 'Gloriana' is the protagonist in Edmund Spenser's epic poem 'The Faerie Queene' (1590). The text is primarily a fictional work, and it can be read on several levels of allegory, including as praise (or, later, criticism) of Queen Elizabeth I.