My ancient dog-eared copy of -

'The War at Sea' (edited John Winton - Arrow Books)

- has a brief personal account of the Battle of the River Plate told by Lieutenant-Commander R.E. Washbourn R.N. - who was PCO (gunnery officer?) in charge of the main director aboard HMNZS Achilles at the time.-

"Exeter, as you know, bore the brunt. We had the attention of the 5.8s all the time, but they weren't very effective. I think that we shot up their control fairly early on, and put at least two of the starboard battery out of action."

(5.8s representing the perceived bore size of Graf Spee's secondayy armament at the time.)