seen for >45secs on the surface, 2 Gt Diving beetles, I assume a mating pair.
No interactions present.
You can't determine the species from these pictures as there are 3 species in that area with that general appearance on top. The key features are underneath.
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
Lat/Lng: 51.6823, -3.7563
OS grid ref: SS786996