Chalk grassland/woodland reserve. Feeding on wild carrot.
No interactions present.
Appart from the obvious - a female has a sting! The other ways to separate M/F, males have 13 antennal segments, females 12. Males of Ectemnius also have very odd knobbly basal segmets (your photo one), the shape is species specific. Also thier abdomens tend to look thinner. This would make your photos of a male, sadly not good enough to ID to species..
Lat/Lng: 51.33, 0.1922
OS grid ref: TQ528612