How small-tube boilers and 14-inch guns change Orion and Lion

How could the 13.5-inch Orion and Lion classes have been improved into a more capable capital-ship fleet?

Use small-tube boilers and move to 14-inch guns, producing faster ships with a more decisive improvement in fighting power.

The first change is to adopt small-tube boilers, using their power and space advantages to improve performance. A move from 13.5-inch to 14-inch guns would follow if the weapon were available. The combination could produce 24-knot Orions and Lions three or four knots faster than their historical counterparts. The value lies in coordinating propulsion and armament rather than enlarging one feature in isolation.