What changes when 850 psi boilers arrive in 1934?

What changes if the Royal Navy has 850 psi boilers by Warspite's 1934 refit while the 5:5:3 naval-treaty framework stays the same?

The treaty system and earlier fleet remain unchanged; the divergence begins in 1934 as higher-pressure machinery reshapes refits and new construction.

The counterfactual holds the diplomatic baseline fixed before changing the machinery. The Washington Naval Treaty and First London Naval Treaty remain in force, while the Second London framework still fails to become an effective universal limit. Nothing before the 1934 availability date changes; the consequences begin with ships entering refit or construction from then on. The later fleet differences therefore stem from propulsion rather than a rewritten interwar settlement.