No interactions present.
I agree with you that it is one or other of these species, but to quote Jim Porter's caterpillar book "no characteristics have been found to distinguish" these two species in the larval stage.
So the only way to get a full identification would be to rear it through to see the adult moth.
Entomologist and biological recorder
Lat/Lng: 53.448, -2.9371
OS grid ref: SJ378949