Almost certainly rasp marks on the chalk reef left by the movement of limpets - there was not a limpet within 20 feet of these marks? Shows how much they can move around (or have been harvested, of course).
No interactions present.
What a briliant picture and a logical explanations. There's a but!
If you look closely, there is a flat winkle actually creating one track and others on the trails.
On that evidence,I think you might change the ID to Winkle trails.
Lat/Lng: 51.3831, 1.3179
OS grid ref: TR309701