Were enough British 15-inch guns left in the 1950s to build a new super-Renown?
Short answerYes; guns remained from several retired 15-inch classes, alongside 14-inch weapons, though Britain might instead pursue a new design.
NotesThe available pool included surviving 15-inch guns from the Queen Elizabeth, Renown, and Revenge classes. Britain also retained 14-inch weapons from the King George V class. That inventory makes a recycled-gun super-Renown physically plausible in the counterfactual. Britain could instead choose to develop a better gun.