WEBF,
You quoted;
..."Most possible scenarios would be in places where tanker support would be available, increasing the range/endurance/time on station of the Sea Harriers on CAP"....
So, therefore most possible scenarios wouldn't require carrier born Sea Harriers at all!
A flight of SHAR's cannot reasonably defend ANYTHING apart from the CVS itself against a capable sophisticated air threat as there aren't (or rather weren't) enough jets or jocks in the RN's flight sized squadrons.