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I think your discussion says it all..it is an Eristalis. You can't get anywhere with the face stripe alone. The stigma does look quite neat, as in nemorum (interruptus), but I would not want to go to species on that alone and with just one photo from this angle.
My Flickr photos...
Thanks to both. I have caught several of these and definite E. pertinax on the Golden Rod this weekend. This is much smaller than those I have i/d as pertinax and the abdomen is the wrong shape - much more rounded (though you can't see that with this view), so I don't think it is that. I have been looking at Stephen Falk's photo site and am still struggling with them!
Jamie from Briantspuddle
Eristalis do come in a variety of shapes and sizes at this time of year...some pertinax are very small, at the moment. Females would be expected to have a more rounded abdomen, too. Having said that, I was not sure whether the front and mid tarsi were really as pale as they seem, or whether that was the angle of the shot.
Lat/Lng: 50.7, -2.3
OS grid ref: SY8193