Originally thought this might be a turnip sawfly but then saw only one pair of wings + haltares so had to be diptera. This is a soldier fly.
No interactions present.
A turnip sawfly mimic!
BMIG website: www.bmig.org.uk (centipedes, millipedes & woodlice)
BMIG Newsletters ~ www.bmig.org.uk/view/resource/bmig-newsletter
BMIG Bulletins ~ www.bmig.org.uk/view/resource/bmig-bulletin
Lat/Lng: 51.8011, -1.4091
OS grid ref: SP408115