A new sample of very powerful radio sources, defined from the Molonglo Reference Catalogue, was recently compiled by Best, Rottgering and Lehnert (1999). These authors provided redshifts for 174 of the 178 objects in the sample, making the sample 98% spectroscopically complete. Here, redshifts for three of the remaining galaxies are presented, confirming the optical identifications and raising the spectroscopic completeness of the sample to 99.5%; only 1059-010 (3C249) is currently without redshift.