No interactions present.
It is one of the six Neoascia sp. I think.
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
with the banding of the legs esp. the rear, I would venture to sugest Xylota segnis, which would fit with the broad band of colour on the underside of the abdomen
It is not X. segnis. It is far too small for a start (less than half the length of a Cuckoo-flower petal), and the first picture shows that it does not have a large patch of red on top of the abdomen. X. segnis is a much larger and more robust fly, with a different jizz, and almost never seen on a flower. It harvests pollen and honeydew etc. from leaf surfaces. Having said that, I would not stake my life on it being Neoascia from the angles given.
Lat/Lng: 52.2, -3.4
OS grid ref: SO0560