AS REGULAR as the arrival of the Rockhopper penguins, one of the sure signs of summer in the Falklands for the last twenty years has been the sighting in the streets of Stanley of Major Ronnie Spafford, leading yet another small group of eager visitors, usually of mature years, but often wearing, with varying degrees of self-consciousness, sweatshirts of psychedelic hue, emblazoned with the words Falklands Experience. Ronnie makes us wear them, you know, one lady recently confided.