Stygnocoris sabulosus
This was found by suction and was about 2.6mm long. Its identification was fairly straightforward although the ventral spines on the front femora weren't particularly easy see (I'm not sure I could see all four on either leg but one may have broken off).
Peritrechus geniculatus showing dorsal hairs and front femoral spines, Wendling Beck Environment Project (Norfolk, UK), 25th August 2025