 He worked for a time with William Weir, a skilful architect in the repair of old buildings and churches, such as Salle, in Norfolk, on behalf of the Society for the Protection of Ancient Buildings, and The Priest's House at Muchelney.He also assisted Ernest Barnsley, supervising the completion of Rodmarton Manor when Barnsley died in 1925, most notably the chapel (1929).Rodmarton was Ernest Barnsley's most important work; ‘probably’, Jewson wrote, ‘the last house of its size to be built in the old leisurely way, with all its timber grown from local woods, sawn on the pit and seasoned before use.’
In 1925, he purchased Owlpen Manor, whose repair is often considered his outstanding work.