Armstrong studied musical composition, violin and piano at the Royal Academy of Music where he was awarded the Charles Lucas prize and the Harvey Lohr scholarship for composition. He was also awarded the FTCL Fellowship in composition, and won the GLAA Young Jazz Musician of the Year in 1982. Upon graduation he became resident student composer for the London Contemporary Dance School. Upon completing his studies, Armstrong served as Music and Dance specialist at the Strathclyde Regional Council in 1984.