Why a pre-Washington bonus ship would not be a third Nelson

If each major navy received one extra capital ship around the Washington Treaty, would Britain build a third Nelson?

Only after the treaty; before it, the available British choices were an Admiral-class revival or a G3 design.

The viewer proposes giving Britain, the United States, and Japan one additional capital ship around the Washington Naval Treaty. Nelson and Rodney were treaty products, so a pre-treaty authorization could not simply produce a third Nelson. Britain's available frozen or planned options would instead come from the Admiral-class line or the G3 design. A plausible counterfactual must respect the sequence in which designs, treaty permissions, and construction decisions became available.