Working from the (somewhat incestuous) bibliographies in British Radio Drama, Contemporary Authors, Contemporary Poets, and The Dictionary of National Biography, here's a nearly complete list of Henry Reed's writing for radio, including his translations from French and Italian (but not his talks or criticism):

• Noises (4 March 1946)
• Noises—Nasty and Nice (1947)
• Moby Dick: A Play for Radio from Herman Melville's Novel (26 January 1947)
• Pytheas: A Dramatic Speculation (25 May 1947)
• The Unblest: A Study of the Italian Poet Giacomo Leopardi as a Child and in Early Manhood (9 May 1949)
• The Monument: A Study of the Last Years of the Italian Poet Giacomo Leopardi (7 March 1950)
• Return to Naples (17 August 1950)
• Canterbury Cathedral: An Exploration in Sound (with Elisabeth Lutyens, 7 November 1950)
  
• A By-Election in the Nineties (3 March 1951)
• The Dynasts (adapted from Thomas Hardy, 3-9 June 1951)
• Malatesta (translation, Henry de Montherlant, 26 February 1952)
• The Streets of Pompeii (16 March 1952)
• The Great Desire I Had: Shakespeare and Italy (26 October 1952)
• Westminster Abbey (with Elisabeth Lutyens, 1953)
• A Very Great Man Indeed (7 September 1953)
• All for the Best (translation, Luigi Pirandello, 22 November 1953)
• The Private Life of Hilda Tablet: A Parenthesis for Radio (24 May 1954)
• Hamlet; or, The Consequences of Filial Piety (translation, Jules Laforgue, June 20 1954)
• The Battle of the Masks (translation, Virginio Puecher, 6 September 1954)
• The Queen and the Rebels (translation, Ugo Betti, 17 October 1954)
• Emily Butter: An Occasion Recalled (14 November 1954)
• The Burnt Flower-Bed (translation, Ugo Betti, 23 January 1955)
• Vincenzo: A Tragicomedy (29 March 1955)
• Holiday Land (translation, Ugo Betti, 5 June 1955)
• A Hedge, Backwards (29 February 1956)
• Crime on Goat Island (translation, Ugo Betti, 7 October 1956)
• Don Juan in Love (translation, Samy Fayad, 5 November 1956)
• Alarica (translation, Jaques Audiberti, 22 September 1956)
• Irene (translation, Ugo Betti, 20 October 1957)
• Corruption in the Palace of Justice (translation, Ugo Betti, 19 January 1958)
• The Auction Sale (poem, 20 September 1958)
• The Primal Scene, As It Were: Nine Studies in Disloyalty (11 March 1958)
• Not a Drum Was Heard: The War Memoirs of General Gland (6 May 1959)
• One Flesh (translation, Silvio Giovaninetti, 12 June 1959)
• The Land Where the King Is a Child (translation, Henry de Montherlant, 3 October 1959)
• Musique Discrète: A Request Programme of Music by Dame Hilda Tablet (with Donald Swann, 27 October 1959)
• The House on the Water (translation, Ugo Betti, 3 February 1961)
• A Hospital Case (translation, Dino Buzzati, 22 November 1961)
• The America Prize (translation, Dino Buzzati, 18 June 1964)
• Zone 36 (translation, Dino Buzzati, 22 March 1965)
• The Complete Lessons of the War (poems, 14 February 1966)
• The Advertisement (translation, Natalia Ginzburg, 24 September 1968)
• Summer (translation, Romain Weingarten, 3 October 1969)
• The Two Mrs. Morlis (translation, Luigi Pirandello, 8 November 1971)
• The Strawberry Ice (translation, Natalia Ginzburg, 21 January 1973)
• Room for Argument (translation, Luigi Pirandello, 7 January 1974)
• The Wig (translation, Natalia Ginzburg, 23 March 1976)
• Like the Leaves (translation, Giuseppe Giacosa, 24 May 1976)
• Duologue (translation, Natalia Ginzburg, 3 January 1977)
• The Soul Has Its Rights (translation, Giuseppe Giacosa, 22 June 1977)
• Sorrows of Love (translation, Giuseppe Giacosa, 23 October 1978)
• Moby Dick (new production of 1947 play, 2 February 1979)
• I Married You for Fun (translation, Natalia Ginzburg, 7 January 1980)

It's likely some of the dates are incorrect, owing to frequent rebroadcasts and re-adaptations, and I've yet to find a record for the broadcast in 1953 of Reed's collaboration with the composer Elizabeth Lutyens on her BBC-commissioned Westminster Abbey. Still, this should be a fairly accurate and (almost) plenary list.

Is this the humble beginning of Henry Reed's writing career with BBC radio?

Roger Savage, writing in the book British Radio Drama (1981), says Reed's first original writing for radio was a 1946 piece called Noises, produced first in a fifteen-minute version for an interlude between programs, and then extended to a full half-hour. Martin Armstrong, in The Listener, described the piece as


British Radio Drama includes a bibliography of Reed's radio plays and the dates of their premieres—Noises is listed as having first aired on the BBC on March 4, 1946:


As you can see, the only "Interlude" scheduled is a five-minute break on the Light Programme at 7:10 p.m., although there is a fifteen-minute "Forces' Favourites" at 7:45 which could be a candidate.

The extended version of Noises which Armstrong reviewed for The Listener was broadcast later that year, on November 18, 1946, at 6:00 p.m. By that time, the Third Programme had been created, and the piece had earned a subtitle (as many of Reed's plays would) "A satirical programme":


Unfortunately, in some books the play is also listed as Noises On (as in the opposite of "noises off-stage"), and the longer version as Noises—Nasty and Nice, causing me all sorts of difficulties in searching and pinning down dates and times.