A robust hoverfly with stripes on its thorax
No interactions present.
I've agreed, but this looks like a female, and they can only be told from Helophilus hybridus, with certainty, by seeing the hind tibiae. The tibiae are 2/3 black in hybridus and only 1/3 or so in pendulus. Really, that can't be judged easily in this picture, though what is visible makes pendulus seem likely.
My Flickr photos...
Lat/Lng: 50.8897, -2.3807
OS grid ref: ST733100