At the age of 15 he won a scholarship to the National Training School for Music, where he studied composition with Arthur Sullivan and the organ with John Stainer.
[1] After a brief series of posts (Holy Trinity Sloane Street and St. Margaret's, Westminster), in 1893 he was appointed Organ Professor at the Royal College of Music.
[1] In 1916 he became organist of Salisbury Cathedral where he oversaw a strictly faithful restoration of the famous Father Willis organ,[2] even going to such lengths as to refuse to allow parts of the instrument to leave the cathedral in case any unauthorised tonal alteration were made without his knowledge[3] while allowing some discreet additions in the original style of the organ (as well as modernisation of the organ's actions) by Henry Willis III, the grandson of Father Willis.
[2] Between 1917 and 1924, Alcock, with Charles Harford Lloyd, juggled the post of Director of the Madrigal Society, to assist the ageing Sir Frederick Bridge, who had been appointed to the role in 1888.
[9] In an obituary tribute Sir Thomas Armstrong wrote of "his firm foundations of good musicianship and sound tradition" and added: What brilliance there was in his passage-work!