Found on garage ceiling, occupant long gone.
No interactions present.
Thanks for the ID Martinjohn, I think I remember having the larvae of the same species on a garden plant in the back yard some years back, the plant is now gone but with a bit of luck I'll be able to find some images of both caterpillar and the plant in question.
Lat/Lng: 55.0606, -6.0593
OS grid ref: NW408815