How different would British naval aviation be if it had access to the Sea Harrier II or Harrier II?
Short answerBritain would probably build or adapt the improved version, since it already possessed the underlying Harrier design tradition.
NotesThe answer begins from industrial lineage rather than treating the aircraft as foreign technology appearing from nowhere. British firms developed the Harrier concept, so a later improved airframe would fit an existing body of engineering and operating knowledge. The Royal Navy could copy the enhanced model and make limited changes for its own requirements. An evolutionary adoption is therefore more likely than a fundamentally different naval-air strategy.