By 1934, the original site had become inadequate and 3½ acres of adjoining land were purchased for expansion. Although car body production was coming to an end, major contracts for the GPO were obtained during the 1930s, for telephone repair vans in the main, on either Morris Minor or larger Morris Commercial Chassis, although two specials were BLB444 of 1934 the blue streamlined van designed to publicise the air mail service, which was modelled as a Dinky Toy. and GPO1 which was a Morris Commercial Leader tractive unit coupled to a Brockhouse semi-trailer upon which Duple built a travelling post office for use at agricultural shows, race meetings and other major public events.