In the film, the meeting appears to happen almost immediately after Graf Spee enters harbor. The actual interview took place at noon on 14 December, with time allowed for diplomatic appointments and courtesies. Britain's naval predominance and the apparent military strength of Britain and France in 1939 did not entitle their representatives to demand an immediate audience. Even under wartime pressure, turning up uninvited at Uruguay's foreign minister's residence would have breached diplomatic protocol.
Notable Point · 2:55-4:13
Diplomatic protocol and the noon meeting in Montevideo
The film compresses the timing of the diplomatic meeting; in Montevideo, even representatives of major powers still had to arrange appointments.