The only point in Helicopter AEW is when you don’t have a proper carrier/airstrip to launch a proper AEW aircraft. The E3D Sentries can do a much better job of that from RAF Mt Pleasant.
The Su-24 is not a fighter, although it can carry short range infra-red missiles. But that is a moot point unless the British have AEW flying and at least 12 Typhoons with some airborne. If these Su-24M Fencer D carry KH-59 cruise missle with a 110km range and AS-11 and AS-12 anti-radiation missile, then they could take out the air field and anti-aircraft missiles in one sortie. A few KH31A anti-ship missiles will take out whatever surface ship the British have. All that would remain is the British sub fleet, which can slow down or possibly stop a full naval invasion, but are vulnerable to ASW and can do nothing to stop paratroopers backed up by merchant ships carrying marines and supplies. I’m assuming certain weapons are sold, and a relatively high degree of competence and deployment ability for the Argentinians. In so far as the former flagship of their navy recently sunk in harbor from neglect, I don’t see an invasion any time soon. But those gas fields are tempting.