Urophora stylata
This was potted off Spear Thistle. For some species of Urophora apparently it's necessary to examine the aculeus to confirm the ID. I don't think that's really necessary for this species but since I had the specimen I thought it was worth checking. The wing was 4.8mm long.
female Urophora stylata showing wing, ovipositor and aculeus (including close-up of tip), Wendling Beck Environment Project (Norfolk, UK), 11th June 2025
This male was found on Ox-eye Daisy at a nearby site a couple of days earlier.
male Urophora stylata, Wendling Beck Environment Project (Norfolk, UK), 9th June 2025