The Royal Navy's slow move to the 5-inch/62 gun

Is the United Kingdom transitioning to a 5-inch/64 naval gun?

It is moving to the 5-inch/62 on Type 26, with later ships likely to follow, but the transition is very slow.

The designation in the question is corrected from 5-inch/64 to 5-inch/62. The Type 26 frigate is the confirmed Royal Navy platform for the weapon. Later classes will probably continue in the same direction rather than treat it as a one-class experiment. The transition is described as glacial because a fleet-wide gun standard changes slowly when new weapons arrive only with new hulls or major refits.