The fly was hovering low down no more than 10 cm from the ground, and several times lunged forwards almost touching the surface before quickly darting back.
No interactions present.
When looking at the photographs later, I noticed what I at first thought was some sort of parasite attached to the end of the Fly's abdomen. But after a search of the internet it seems it may be eggs. Apparently the females coat their eggs in fine sand or soil to disguise them before flicking them into the nests of solitary bees and wasps. So perhaps the darting down closer to the ground may have been egg laying behaviour?
Links to information on coating the eggs;
Does anyone have any further information on this behaviour?
Lat/Lng: 51.30791, -0.74267
OS grid ref: SU877572
Recently cleared sandy bank in wet woodland.