His compositions range from light orchestral music and works for brass band to more serious and extended orchestral works (such as his Symphony from 1983 and the Concertante Dances) as well as church music,.[4] His Magnificat and Nunc dimittis in C of 1965 incorporate Latin American rhythms.[5] Lighter orchestral works include the Cuban Suite, the New Orleans Suite, Divertissement, and two Leicestershire Schools Symphony Orchestra commissions – the overture Sancho Panza (1969) and the Sinfonia Concertante (1967). His works for brass band include Brass Bagatelles, the overture Provence and the Divertimento for Brass.[6] In 1961, Kelly wrote the piano piece Tango for Peter Katin.
Instrumental solos and educational music are also important to him: for example, the Whodunnit Suite for trumpet and piano includes movements entitled: 'Poirot (Detective)', 'Lavinia Lurex (Actress)', 'Colonel Glib (Retired)', 'Miss Slight (Spinster of This Parish)', 'The Chief Suspect' and 'The Chase'.[7]
Recordings
Two CDs of Kelly's orchestral music have been issued by Heritage.[8]
Volume One (2014): Left Bank Suite, 'Epitaph for Peace' (from the two movement Lest We Forget), A Christmas Celebration (five movements), Concertante Dances, Globe Theatre Suite (for recorder and strings), and Nativity Scenes. Heritage HTG CD284 (2014).
Volume Two (2021): Fantasy Overture: San Francisco; Calypso’s Isle; Concerto da camera; Four Realms Suite, Capricorn, A Christmas Dance (Sir Roger de Coverley), Concerto for Two Trumpets, Comedy Film for orchestra. Heritage HTG CD180 (2020).
The choir of Clare College, Cambridge, issued a CD of the choral music in 2001, including the cantata Crucifixion, the Missa Brevis and the popular carol This Lovely Lady.[9] There is a non-commercial recording of Kelly's Symphony No 1 (1983), by the City of Oxford Orchestra, director Yannis Daras, available on YouTube.[10]