Britain's enormous post-World War One shipbuilding advantage

Did Britain have more naval infrastructure before World War One than immediately before World War Two?

Yes, and it retained even more just after World War One, when many yards could compete for new capital-ship orders.

Britain emerged from the First World War with more naval and maritime infrastructure than it possessed immediately before the Second and perhaps even immediately after it. Existing yards let the Admiralty order ships without first financing entirely new industrial plant. Competition among roughly a dozen builders for four G3 contracts reduced prices substantially. That industrial depth helped make the design unusually cost-effective for its combat power and explains why British ordering did not require the same advance public schedule as American construction.