Movietone News from March 21 1940 HMS Achilles’ return to New Zealand following her action in the Battle of the River Plate on 13th December 1939.
Skoblin has many more contemporary Newsreel videos on YouTube.
HMS Achilles' return to New Zealand
Earlier in the war: The first bombing raid on Germany
Later in the war: RAF attack Sylt after Luftwaffe attack on Scapa Flow