Royal Navy turret naming conventions

What was the Royal Navy's formal policy for naming main-battery turrets?

Four-turret ships commonly used A, B, X, and Y, but ships with additional turrets required different practical naming schemes.

Turret labels were a practical convention rather than an immutable rule. Four-turret arrangements fit the familiar A, B, X, and Y sequence. Ships with additional mounts needed schemes adapted to their actual layout, including named rather than lettered turrets in some cases. Plans must therefore be read without assuming every navy or hull followed one universal pattern.