The theme tune "Alley Boogie" was chosen by the writer David Renwick because he a) listens to a lot of jazz and b) thought Alice's colleagues' nickname "Allie" for her made a pleasing match.
Writer David Renwick actively wanted Gill to be American, as he likes writing in the American idiom.
The locations department had roamed far and wide to find a property to act as Gil's house, but it was eventually found by the producer Verity Lambert, close to where she lived in Totteridge, and within easy reach for filming.