What if an accident had occurred onboard an RN SSN during the Falklands War, resulting in her loss? The accident can be either one where the sub can still surface and get (almost) everybody off, or one where the first idea anyone has that an SSN is in trouble is when SOSUS hears an explosion followed by breaking up noises.
What would the results be? Presumably the RN has more than one SSN, so Belgrano may or may not still be toast. What effects would this have on the rest of the Falklands War, and on the RN to the present date?