Approximately 10mm long. Roughly oval shaped body with square front of head. Dark brown/black in colour.
No interactions present.
Yes it is a lesser water boatman. You could add the family name (Corixidae) as a revision.
Lat/Lng: 52.568102, -0.277969
OS grid ref: TL168980
Group of ponds set in several acres of grassland. There are small areas of wildflower meadow and woodland on the site.