Found lying on beach just as in the picture - probably washed out of the sand with recent high tides and strong winds. Length approximately 20cm.
No interactions present.
On the picture there is a clear view of the three annulations between chaetiger 2 and three that separate this species from the similar, and relatively recently described, species A.defodiens.
Lat/Lng: 60.2, -1.4
OS grid ref: HU3857