CAW,
I do not recall how often QRA launched for a CAP out to the west, but when I was OC Eng from mid Aug 84 - end Dec 84 we certainly had one "live" scramble in the early morning (0500 or so) which turned out to be a USN (or possibly US Coastguard) P3 which I was told was in transit from ASI to Chile and which had been on the ground at ASI the day before. No doubt one of the F4 operators will recall more details and may even know why there was, apparently, no flight plan received at Stanley.