It didn't stay long enough to get a dorsal view.
No interactions present.
Possibly a Melanostoma, but not sure.
My Flickr photos...
The spots on tergite 2 look rather large for Xanthandrus, and don't appear particularly round (rather pointed at front end?). The halteres are also very pale...they are darker in the two specimens which I have of Xanthandrus. Not an easy angle, though...
Age , seasonality of the specimen are all factors the halter not usually taken as a key ID feature . with Digital the colour balance exposure and other factors are also difficult from photos including the angle which will distort perspective Have you a link to your specimens ?
Whats Happening with Nature ??? Visit the Nature Blog
Supporting FEET Conservation work & Biodiversity Recording
You may be right, but it's mainly the shape of the spot on tergite 2 which seems wrong, as it is apparently pointed at the front end? The fly also looks pretty small on the grass head (though that is difficult to judge), and Xanthandrus is a relatively large fly. On a grass head is an obvious place for a Platycheirus or Melanostoma, but not for Xanthandrus.
Not sure! It's good to debate the possibilities, though.
Lat/Lng: 51.2699, -0.1453
OS grid ref: TQ294539