Without a battleship holiday, King George V evolves from Nelson

What battleships would Britain have under construction in 1939 without the treaty building holiday?

Probably an improved Nelson-derived class rather than the historical King George V design.

Ending the battleship holiday earlier changes both timing and Admiralty leadership. A class begun near the Nelson era would start from a different design environment than the historical King George V class. It would probably develop Nelson and Rodney's layout and armament instead of waiting for the choices made in the later 1930s. The result would be a different lineage carrying the King George V name, rather than the ships built historically.