I emailed the photograph to Taff Gillingham, our WFA chairman, he relied "All three are wearing the Other Ranks brown drill overalls which replaced the white Great War style and would, in turn, be replaced by Overalls, Denim in 1938.
By this time Regular Army Officers would all have been wearing the Mills private purchase web equipment and it is very, very interesting to see TA Officers still wearing double-harness Sam Browne's in Battle Order."