Did the Royal Navy need a missile between Sea Wolf and Sea Dart?
Short answerNot really; point and area defense covered the useful roles, and a medium-range missile is poor value in a cell that can carry a longer-range weapon.
NotesSea Wolf protected the ship at short range and Sea Dart defended a wider area, leaving little operational value for an intermediate system. The same logic makes Aster 15 unattractive in a full-size cell that could carry Aster 30, while Sea Ceptor supplies shorter-range coverage from separate compact launchers. Medium-range weapons become worthwhile when several can share the space of one long-range missile.