Herbert attended evening classes in architecture between 1914 and 1919 at the British Museum, the Victoria and Albert Museum, and the Central School of Arts and Crafts. Herbert also studied part-time at the Architectural Association. By the time he had completed three years there he was an experienced builder, aged thirty-four, and trading under the name of Herbert and Co.
Having passed the Society of Architects Examination he was elected a Member of the Society on 1 September, 1921. On the Society of Architects and the Royal Institute of British Architects merging, in 1925, he automatically became an Associate of the RIBA. In his statement supporting his application to become a Fellow of RIBA, in 1940, he listed his work. This included various estates in Southampton, private houses in Hampshire and Sussex, and Village Halls in Chichester, Littlehampton, and Wood Green Village, near Fordingbridge. This concentration of village halls seems to reflect his early work at Letchworth and his friendship with Ebenezer Howard and Raymond Unwin, the town planners.
Thus from as early as 1900, the boys were exposed to other influences besides their father and his workmen. The latter, who had all leamt their skills at the end of the Victorian period, were used to building in the Queen Anne style. By the time the boys were learning, Parker and Unwin, Voysey, Baillie Scott, and Lutyens, were all building in Hampstead Garden Suburb and Herbert Collins was much influenced by them. Herbert also worked for about eighteen months on the early stages of Welwyn Garden City and was always interested thereafter in the garden city concept. In 1906 he started building the west side of Rookfield Avenue, using roughcast walls, large gables, and corner windows with small panes. The same influence can be seen in Fortismere Avenue, which is built in a completely different style from nearby Leaside and Birchwood Avenues.