Erigone atra
These were in a pitfall trap (in propylene glycol, so no live photos) along a beetle bank in an arable field. The toothed edge to the carapace and rather whacky pedipalps looked very familiar so I think it's a species I've seen before but not had the resources to identify.
male Erigone atra showing head from side and pedipalps (2 views), Wendling Beck Environment Project (Norfolk, UK), 29th to 31st March 2024
second male Erigone atra showing pedipalps (3 views), Wendling Beck Environment Project (Norfolk, UK), 29th to 31st March 2024