I also believe the Fencer sale is a hoax. 28th december is the "dia de los inocentes" in the spanish speaking world - their equivalent to april fools day.
Having said that, i have absolutely no doubt that The Soviets were providing satellite intelligence to the Argentine Air Force during the war, and there is also the Invincible torpedo incident from the 5th May that has yet to be fully explained. I have spoken to eye witness of this, and they were pretty sure the saw a torpedo wake, and Brillants sonar operator was very convinced by what he heard......no argentine subs were in the vicinity of the CBG at the time.