Why Lion would not simply reuse Nelson’s turrets

Were Lion-class battleships intended to use Nelson-class guns or even receive Nelson and Rodney’s existing turrets?

No; Lion used improved guns and turrets based on Nelson experience while the older ships retained their own armament.

Nelson and Rodney were expected to serve alongside the projected Lion-class battleships, so stripping their main armament was not a practical plan. The Lion programme instead developed new turrets informed by the earlier Nelson machinery. Its 16-inch guns likewise evolved from Nelson’s weapons rather than duplicating them unchanged. The distinction matters because design lineage does not mean that an older mounting can be transferred directly into a later ship.