No interactions present.
BMIG website: www.bmig.org.uk (centipedes, millipedes & woodlice)
BMIG Newsletters ~ www.bmig.org.uk/view/resource/bmig-newsletter
BMIG Bulletins ~ www.bmig.org.uk/view/resource/bmig-bulletin
Head waving is a technique used by some larvae (e.g. Lackey moth larvae) to 'scare off' predators rather than searching for food. This may be what you saw.
Lat/Lng: 51.623993229532, -1.1063039302826
OS grid ref: SU619920