The Sacconi, without whom no Music at St Peter’s season would be quite complete, make their 15th visit to Wallingford since 2005 (including their Mozart quintet series in 2006 and their Beethoven quartet series between 2009 and 2011) this year they perform two great classic Viennese quartets and an English work described by the composer as “a serenade for someone I never met.” It was commissioned in 2001 to commemorate the infectious energy of a devoted chamber music enthusiast, and is in six short movements.