A fly sunning itself (herself) on ivy. I was absolutely sure this was a blow fly, but it turns out not - house fly (Muscidae).
No interactions present.
Looks more like a female Eudasyphora cyanella (Muscidae). http://www.diptera.info/photogallery.php?photo_id=4360
Agree E. cyanella because of the venation
Lat/Lng: 51.072, -0.69
OS grid ref: SU918311
On ivy in my garden, in mixed broadleaved woodland, altitude 238m, oak, birch, chestnut and willow nearby.