Anyone from St Margaret's who saw the company at the festival this week would not therefore have been surprised by "Stravinsky Violin Concerto'', the opening piece in the first programme. Male dancers, initially at least, grabbed the limelight with their high jumps and rapid fire turns.
The men wore a simple garb of plain white T-shirts and socks, with black tights. No, they did not stick to the tracksuit bottoms they had worn at St Margaret's; the 13-year-olds had scorned the idea of men in tights. Even they would have accepted, however, once they had seen the scope of movement required by Balanchine's choreography, that tights were the most suitable garments for clean line and easy stretch.
Two pas de deux of contrasting movement followed, one portraying a relationship full of rivalries, the other tender love. "A Capprice" then brought 20 dancers togther in a moving geometry of line, squares and circles.
But lest the youngsters thought they had seen all the ingredients a dance production had to offer, there were more lessons. Colour is another of dance's important devices. If the first piece appeared starkly cool, the next, "Sonata'', was bathed in a warm light rendering the dancers like slow, slender flames of a kindling fire.
"Sonata'', choreographed by Helgi Tomasson, the company's artistic director, is a ballet performed to the mesmeric melodies of Rachmaninov's Sonata for Cello and Piano (in this production the musicians performing on stage). Even St Margaret's boys, impatient for some rock and pop, might have been seduced by the delicately luscious score and the willow-like strength, not of the men, but of the female lead.
That San Francisco Ballet was not about to compromise on its essential foundations in the classics, just to conform to the expectations of modern teenage boys, was evident in the last piece, "Symphony in C'', with score by Bizet and choreography by Balanchine. Female dancers appeared in white tutus and point shoes and the male performers in black, one-piece leotards and tights.
But what a privilege it must have seemed to St Margaret's to have known they had worked with such a professional company, sharpening up on their pirouettes and getting some height into their jumps with the help of two of the male supports in this piece, Kester Cotton and Ikola Griffen.
The macho boys would have to have faced another question: with 40 dancers moving fluidly through an array of patterns, was it so bad to get an eyeful of lyricism and grace combined with such brilliant teamwork?