During the very long chase near the end, the light is not consistent with the passing night hours - the chase starts off at night, reaches dawn when some crates fall from the truck, is then even early daylight briefly as seen from the car following behind, but then it is suddenly very dark at night again when the chasing car is finally halted by the barb-wire trap.
When Captain Waggett telephones the Post Office, he is unable to get through to the switchboard operator. Seconds later, he is speaking to Mistress Campbell. He could not possibly do so without the Post Office switchboard connecting him.
Had there really been whisky (or really about anything except air) in those wooden crates piled as high as a person on the rowboats the villagers use to loot the cargo ship, those boats would have capsized or sunk by the sheer weight of the crates.