Jack removes his overcoat as he begins running to the motorcycle. He is then seen running, wearing only his suit jacket, but the next time we see him, he is removing his overcoat again.
When Jack is running to get on the motorcycle, you can see that he is wearing white socks. For the rest of the episode (both before and after this), he's appropriately wearing dark socks.
Jack removes his overcoat as he begins running to the motorcycle. He is then seen running, wearing only his suit jacket, but the next time he is seen, he is again removing his overcoat.
Jack removes his overcoat as he begins running to the motorcycle. He is then seen running, wearing only his suit jacket, but the next time he is seen, he is removing his overcoat again.
Jack finds a filtered cigarette at the scene of the crime. Filtered cigarettes were not generally available until the 1950s.
When Phryne climbs over a partition wall into an office at the airfield, the windows in the wall bend and flex, showing that they are made of Plexiglas or another acrylic material. While some of the first uses of acrylic were in aircraft, acrylic sheet wasn't produced commercially until the mid 1930s.