I didn't take a lot of notice at the time as I was taking a lot of photos but this looks like a small insect on the back of another? I think it was around 7mm.
No interactions present.
Cantharids at it......
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
Lat/Lng: 53.6933, -0.4733
OS grid ref: TA009229