just can't figure this one out, so am going for miliscaeva for some reason, can't fit it to the platycheirus, and pelecocera trincincta which seems closest has black scutellum
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Looks like one of the intermediates, with spots on tergite 3 and 4 like auricollis, but on tergite 2 like cinctella. Would have been good to have a head on shot, to see the face pattern.
My Flickr photos...
Lat/Lng: 51.5559, -0.0242
OS grid ref: TQ370859