Time at the Mayfair Hotel
I think there is intended to be some attention paid to the timing of all the events at the Mayfair.
When Diane gets the Las Vegas text, her phone says 19:28, which is 7:28pm.
Later, when Gordon mistakes Albert's question and tells him the time, it's 11:05.
Finally, when Diane looks up the coordinates, the bar is closed. You could assume this means it's probably midnight or later.
This indicates that everything is happening linearly within the Mayfair, but it seems odd that they go to great lengths to show the time that things are happening. Who knows, maybe it's nothing!