Preserving Britain's interwar armour industry

How much more armor-manufacturing infrastructure did the Admiralty want in the 1930s?

Enough steady work to stop plants and skills disappearing; maintaining that core could cut ship delays and enable rapid wartime expansion.

Extra armor-making capacity could have accelerated the King George V class and other ships by about a year because thick plate was a long-lead item. The key investment was not necessarily a new factory: steady orders for ships, coastal-defense turrets, or other armored work could retain a skilled core and enough machinery to expand rapidly toward much of the pre-1914 output.