The end of the war did not bring any respite in concert-giving for the choir. In all, twelve concerts were held during 1946. In June, a Handel Festival was promoted at the Royal Albert Hall, comprising a "Victory Concert", Solomon, Acis and Galatea and selections from Israel in Egypt and Messiah, but, sadly, this seems to have been an idea too far in advance of its time, resulting in disappointingly small audiences and meagre box office receipts.
The year 1951 brought an invitation to send a "balanced contingent" to take part in the ceremonial opening of the Royal Festival Hall on 3 May in the presence of King George VI, along with representatives of other leading London choirs. The patriotic programme started with the National Anthem and continued, via "Zadok the Priest", "Blest Pair of Sirens", "Rule Britannia", "Soul of the World" and "Pomp and Circumstance No 1" to the "Hallelujah" and "Amen" Choruses from Messiah.
From this time, the GCU made regular appearances at the Royal Festival Hall and in December 1951, the tradition of performing Messiah as well as two carol concerts was established.

The composer Ralph Vaughan Williams
and the GCU's music director Frederick Haggis
in discussion during a rehearsal of Epithalamion in 1957.
The choir's concert and broadcast performances continued through the 1950s, including the first UK performance of Mahler's Das Klagende Lied, sung in German, under the direction of Walter Goehr. The programme also included one of the first postwar performances of the "Magnificat" from Monteverdi's Vespers, in which the soloists were Jeanette Sinclair, Joan Sutherland, Norma Proctor, Wilfred Brown and Peter Pears.
Another UK première, in 1957, was Reizenstein's Voices of the Night, conducted by Josef Krips, followed later in the same year, by the first UK performances of Stravinsky's Les Noces with the Royal Philharmonic Orchestra and Richard Austin, and, in September, the first performance of Vaughan Williams' Epithalamion.
In 1958, rehearsals were transferred from the Cathedral Hall, Westminster, to St. Michael's School, Graham Terrace, which, it was hoped, would be more suitable "with the relatively smaller dimensions of the choir". The GCU had by now become a self-governing organisation. Frederick Haggis's annual newsletters, which were sent to all the members at the beginning of each season, show that choir's main problems were the ones that always seem to trouble every choral society: money (or the lack of it) and the attendance (or otherwise) of choir members at rehearsals. There are the reminders and pleas, familiar to every choral singer, to attend the maximum number of rehearsals, to arrive on time and not leave early, to pay subscriptions promptly and to sell, sell, sell tickets for all the concerts.
In 1962, the GCU took part in a concert at the first City of London Festival in St. Paul's Cathedral. The choir was conducted on that occasion by Sir William Walton in his own work "In Honour of the City of London."
In 1971 Frederick Haggis celebrated his 85th birthday and conducted a special performance of The Dream of Gerontius, in which the GCU was augmented by former members and friends from other choral societies, demonstrating perfectly the "family feeling" engendered in the choir. The year 1971 also saw the appointment of Brian Wright as Associate Conductor of the GCU. He conducted Rossini's Petite Messe Solennelle at St. John's Smith Square, in the autumn. He also conducted the traditional carol concerts, while Mr Haggis conducted Messiah.
Over the next two years, Frederick Haggis relinquished more and more of his conducting commitments with the choir. Brian Wright was already in the process of raising musical standards, especially to conform with new ideas about the performance of baroque music. Now he played an increasing role in conducting performances by the GCU.