The Ibbs and Tillett brochure has this resumé:

A list of engagements, showing the date, venue, work, soloists and orchestra, choir, accompanist and conductor, compiled from John's programme collection, can be read in the book about his life and career,  shortly to be available from Lulu.com and  Amazon etc., and written by his daughter Janet Kinrade Dethick. 



Below are the oratorio engagements in 1961 for which there is a programme:


In addition, there was a celebrity concert in Scotland.  The Dublin performance of The Messiah was broadcast by Radio Eireann



After an audition in 1953 John Dethick appeared regularly on BBC Radio. The BBC Genome records 39 appearances, and there are two others in which his surname is spelt  wrongly (Dethic and Dedhick)

In addition to the broadcasts mentioned on the Home Page here is a brief summary:


Oratorio/Serious songs

Brahms A German Requiem   Leeds Philharmonic Chorus. Yorkshire Symphony Orchestra  conducted by Sir Malcolm Sargent

J.  S. Bach  St. John Passion   BBC Midland Orchestra   Conducted by Roy Henderson

A. Honegger   A Christmas Cantata    Sheffield Philharmonic Chorus    Halle Orchestra     Conducted by Hermann Lindars

C. V.  Stanford    (Songs of the Sea)    BBC Northern Orchestra    Conducted by Stanford Robinson

G. F. Handel    Israel in Egypt    The Bach Choir    The Jacques Orchestra    Conducted by David Willcocks

R. Vaughan Williams    Songs of Travel    (BBC Midday Proms)    BBC Northern Orchestra   Conducted by Stanford Robinson

Mozart   Benedictus siit Deus (K117) Motet;   Vaughan Williams  Lord thou hast been our refuge;   Beethoven arr. Weingartner Grosse Fuge;   Mozart Mass in C (K337)    BBC Chorus   St. Cecilia Orchestra  Conducted by Charles Groves



A series of song recitals accompanied by Ernest Lush, Clifton Helliwell, Josephine Lee, Frederick Stone  and Keith Swallow



Two appearances on Music Making with the Northern Sinfonia Ensemble and Keith Swallow


Brass Bands

Four performances with the Brighouse & Rastrick Brass Band conducted by Eric Ball and Trevor Walmsley

Two perferomances with the Manchester C.W.S. Band Conducted by Alec Mortimer



Two performances on 'Those were the Days' with Harry Davidson and his Orchestra