In the "Poirot: The Theft of the Royal Ruby" there's a side plot of Desmond Lee-Wortley calling someone (later revealed by Poirot to be repair service at the nearby airfield) and being surprised that something (later revealed to be an airplane) will not be fixed by December 23rd.
There's even I phrase (not direct cite):
What? How? You've said it will be done at 23rd
However the call takes place on Christmas Morning.
How can be calling repair service at that time (wouldn't it be closed, as the entire airfield)? And how can he be surprised asking about data that was two days earlier?
Am I missing something or is there a hole in a plot here?