Common Whirligig Gyrinus substriatus
 (2).jpg)
 (1).jpg)
Common Whirligig Gyrinus substriatus, North Elmham (Norfolk, UK), 4th July 2018
 (1).jpg)
 (2).jpg)
Common Whirligig Gyrinus substriatus, North Elmham Cathedral Meadows (Norfolk, UK), 30th June 2019
 (1).jpg)
 (2).jpg)
 (3).jpg)
 (4).jpg)
Common Whirligig Gyrinus substriatus, North Elmham (Norfolk, UK), 16th July 2019
The above beetles either came to light or were netted in flight, but I see Whiligigs more often on the surfacfe of the water. Unfortunately when they're doing this I can't see sufficient detail to identify them. I imagine they're most likely substriatus, but can't assume that's the case.
2x Gyrinus sp., North Elmham Cathedral Meadows (Norfolk, UK), 24th April 2020