How new cruiser classes released older ships for other roles

If Crown Colony cruisers replaced the C and D classes, what was intended to replace the E class?

Probably more Crown Colonies or their successors, although Belfast and Edinburgh are suggested as the closer match in status and role. New construction increasingly expanded the fleet while older cruisers remained in use.

Royal Navy cruiser replacement plans changed as preparations for war accelerated. Dido-class cruisers could assume fleet and destroyer-flotilla duties while older C- and D-class ships remained available for distant stations or anti-aircraft conversion. Crown Colony cruisers supplied additional combat power through a simplified development of the Town design. More Crown Colonies or their successors are suggested as the probable replacement for the E class, although Belfast and Edinburgh are proposed as the closer comparison in status and role. Enterprise's distinctive capability complicates even that pairing. As the treaty system broke down, plans moved from replacement to expansion while retaining older ships capable of useful service. A new ship could replace an old cruiser in one assignment without causing the old hull to leave the fleet.