A pair of bee fly 'in cop'
No interactions present.
B. major is the only species in UK that has that solid, almost black leading edge to the wing. That combined with the long proboscis should put it beyond confusion.
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
Lat/Lng: 51.5, -0.4
OS grid ref: TQ1583