Argentina didn't have the military capability to attack anything outside of the war zone. Great Britain simply exercised restraint in their attacks on the mainland.
that is the main point. Any country escalating a conflict outside the war zone would pay a heavy price that would make it not worth it. They wouldn't win the war that way, they'd lose it. It is not their good will, it is just their desire to win, not lose. Bombing Argentina outside of war zone would pit Great Britain against whole world - a loosing position, or not-wining at the very least. You wanna fight - take it outside and everybody is happy.
