Interesting though they are, blackfly are not popular with my wife, especially on her Clematis. So I didn't tell her they were there.
No interactions present.
Lasius, and it might be niger, but it might be a few other things as well. Genus is as far as you should go.
...I didn't know anything about them!
Lat/Lng: 51.95765372803, -0.25604825019832
OS grid ref: TL199302