Dido-class cruisers against Admiral Graf Spee

What if Dido-class cruisers had replaced the Leanders at the Battle of the River Plate?

They would likely close and batter Graf Spee's upperworks with rapid fire, but probably would not sink her outright.

The British cruisers would probably still close because Graf Spee's crew could mistake Didos for destroyers at range. Rapid 5.25-inch fire would strip exposed upperworks and inflict serious damage, but lighter shells would not automatically sink the armoured German ship. The historical Leander-class crews were already highly accurate, so theoretical rate of fire is not the same as effective hits. A later exchange notes uncertainty over whether Graf Spee identified the British ships as J-class or Tribal-class destroyers. The evidence from the captain's writings, ship behaviour, and classes already prominent in service leans toward the Tribals. The counterfactual turns on identification, fire control, and damage mechanism rather than calibre alone.