Could the Iron Dukes have carried 15-inch guns?

Could an Iron Duke-class battleship have been rebuilt with 15-inch guns?

Probably, by sacrificing one turret in an Andrea Doria-style reconstruction and fitting a heavier remaining battery.

The Iron Duke hulls may have been capable of a much more ambitious reconstruction. The likely route would remove one turret, as Italy later did with the Andrea Doria class, and replace the remaining battery with 15-inch weapons. The result might have been more useful than the R class in some respects. This bounded counterfactual is grounded in available hull volume and an actual contemporary reconstruction model.