I’ve boarded many ships in BCN and got a taxi every time. The taxis all know once you tell them which ship you’re embarking asks the security at the port entrance and they will take you straight to the terminal..just have your travel docs.
I used Rome-airport.net. €130 was waiting bang on time in an E class merc straight to FCO …HOWEVER, think the driver thought he was on a F1 racetrack..
Wouldn’t even bother. The whole SA visa website is dreadful.. I just gave up and stayed onboard….and don’t think I missed much judging by the comments of fellow passengers who did go ashore or did tours.