A small, distinctively-marked fly, resting head-down on a concrete pillar.
No interactions present.
I am always wary of distribution maps, as they seem to be changing very rapidly for some species.
I totally agree, which is why I went for 'It's likely...'. There is no evidence I know of for R. strigosus to be expanding its range, though.
My Flickr photos...
Lat/Lng: 52.4515, -0.1889
OS grid ref: TL231852