By 1939, after Oliver Bulleid's appointment as Chief Mechanical Engineer, the locomotives had been outshopped in an unlined black livery to denote their freight status subject to livery experimentation. 'Southern' remained on the tender, though the number transfer was moved to the cabside, both in 'Sunshine Yellow' lettering. During wartime service, a further modification to the livery was made with a green shading on the 'Sunshine' lettering. The final Southern livery reverted to 'Sunshine Yellow' lettering and numbering.
