Stenus clavicornis
This was found by suction sampling. I keyed it using Lott & Anderson and got it to clavicornis before examining the genitalia. Then I checked the aedegaus and fortunately that matched my ID.
female Stenus aceris showing hind leg, hind tarsus, basal tergite, elytra, tergites 6 & 7, other tergites and aedeagus, Wendling Beck Environment Project (Norfolk, UK), 17th April 2025