The expected schedule advantage of a mature, smaller design disappears when New Zealand and Australia are compared with Lion and Princess Royal. Lion took roughly as long to complete as New Zealand, while Princess Royal was completed about seven months before Australia despite being laid down only about a month earlier. Guns and components for the 13.5-inch ships received greater industrial attention because that line represented the Royal Navy's future. Production priority mattered more than nominal design maturity.
Notable Point · 28:24-31:44
Why the older design did not deliver sooner
Construction dates show that choosing the older 12-inch design produced no meaningful delivery advantage because yards prioritized the 13.5-inch production line.