...is apparently doing rather well at the moment.  Certainly I was very surprised to find a few last spring on an apparently undistinguished area of arable margin near Hemington (ST75/VC6).  Less surprising was seeing it on the SSSI chalk grassland of the Long Knoll (ST73/VC6 but administrative Wiltshire), which also has some interesting day-flying moths, a Forester I did not identify and what looks like Five-spot Burnet ssp. palustrella.  I understand discolor is also known from Radstock sidings (ST65/VC6)