A British submarine could have pursued Veinticinco de Mayo

Could Britain have attacked Veinticinco de Mayo in 1982?

Yes; a nearby S-class submarine had an opportunity, though pursuit risked exposing it.

An S-class submarine was near enough and had orders comparable to Conqueror's action against Belgrano. Catching the retiring carrier at high speed risked revealing the submarine, but continued exposure could have led to a second Argentine capital-ship loss.