Na I (left) and K I (right) equivalent width measurements (in Å) as a function of spectral type (4  ≡  M4; 5  ≡  M5; etc.) for all the photometric candidates confirmed as spectroscopic members. Typical error bars on the equivalent width measurements are marked. Some of the latest type members lack measurements for the KI doublet because of the nearby strong oxygen telluric band. The candidates for accretion i.e. which exhibit Hα equivalent widths larger than the empirical boundary defined by Barrado y Navascués & Martín (2003) are highlighted with red squares. The stars lying in the AAOmega field have been added as crosses and shifted in spectral types by  + 0.12 for clarity.