No interactions present.
Gotcha - I hadn't clocked the orientation of the mark on the forewing tip. I had wondered about the lack of dusting, but it could have been an exposure thing.
ID chart I have only shows one spot on each wing for small whites - may be this one (with 2 spots) is a male ?
Lat/Lng: 53.4308, -2.3452
OS grid ref: SJ771927