Dolerus varispinus
Using the RES key this comes out to Dolerus brevitarsus, but if I understand correctly this is the species now known as Dolerus varispinus.
, Cathedral Meadows, 8-May-20 (A) (1).jpg)
, Cathedral Meadows, 8-May-20 (A) (3).jpg)
, Cathedral Meadows, 8-May-20 (A) (4).jpg)
female Dolerus varispinus showing its saw-sheath and mesonotum, North Elmham Cathedral Meadows (Norfolk, UK), 8th May 2020