By 1934, the Southern Region recognised that the short 48in-ex-LSWR stock was in need of some major attention as it was nearing the end of its working life. Much of it was built on wooden underframes, whilst some was still gas lit and so a programme of refurbishment was proposed and undertaken under Works Order (HOO No.) L801 of March 1934 and Works Order (HOO No.) L852A of March 1935.
The 58in-stock to diagrams 99 and 418 were created in 1935/1936 at Lancing Works, by taking the 48in-Composite body, cutting it and fitting to a 58in-Maunsell underframe. In the case of the Brakes, a 10in-guards van was grafted to one end, these were steel panelled, which didnint quite match the finish of the rest of the wooden panelled bodywork. The composites (to diagram 31) differ, in that the original 48in-body was cut into two sections and mounted at each end of the underframe, with a 10in-section being inserted comprising a single compartment, with two lavatories (side by side). The defining feature of all these newin-vehicles was the triangular section weatherboard that ran the length of the body, disguising the join (the 48in-body being narrower than the 58in-underframe).