When Hyacinth asks the alarm-company man for a "dusky pink" alarm box, he tells her that the boxes only come in blue, yet when the box is installed later, it's white.
(At around 19mins) Hyacinth asks the man about the box on the *outside* of the house: "the thing that goes on the wall, the thing that people can see outside". That's what he says can only be blue (although she does get it in dusky pink). The alarm box installed *inside* the house is white.
(At around 19mins) Hyacinth asks the man about the box on the *outside* of the house: "the thing that goes on the wall, the thing that people can see outside". That's what he says can only be blue (although she does get it in dusky pink). The alarm box installed *inside* the house is white.
At around 18 minutes, 52 seconds in, when Elizabeth and Emmet are discussing the alarm installer, Elizabeth says, "He could be hopping about on one leg", and then you can briefly see a microphone at the top of the screen.