Wings transparent and fly-like
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It's a female, with a pointed abdomen. To get to species from a photo, you need a picture of a male from above, so that the bulbous genital capsule can be viewed. Have a look at this site...
My Flickr photos...
Lat/Lng: 51.940878612559, -0.97898483276367
OS grid ref: SP702274
Allotment - vegetables and flowers grown, pond, hedgerow