The Koutras–McIntosh family of metrics include conformally flat pp-waves and the Wils metric. It appeared in a paper of 1996 by Koutras–McIntosh as an example of a pure radiation spacetime without scalar curvature invariants or infinitesimal symmetries. Here we demonstrate that these metrics have no 'hidden symmetries', by which we mean Killing tensors of low degrees. For the particular case of Wils ...