Why would the Royal Navy buy a mini-Renown large cruiser, and what would it do?
Short answerIt would protect and interdict commerce, show the flag globally, lead task groups, and escort carriers with enough firepower to deter or damage a raiding battlecruiser.
NotesIts job is not to defeat a battlecruiser alone, but to impose damage a surface raider cannot afford. Several such cruisers could combine against a raider, while one could lead carrier defenses without slowing the group. Commerce protection, commerce interdiction, and global presence all reward a fast ship with endurance and credible heavy guns. The design fills the widening space between light cruisers and expensive capital ships without pretending to replace the battle fleet.