Large dark hoverfly without yellow abdominal markings.
No interactions present.
You can leave the scientific name in its extended form; but if you want the photo to figure alongside others for pertinax on iSpot, you could enter a fresh ID without Eoseristalis.
Your photos neatly show the difficulties of judging tarsus colour from a photo, as the mid right tarsus is pale on one photo and dark on the other. A trick of the light, but it proves how hard it can be to make a definite ID of these, sometimes.
My Flickr photos...
Thanks, ophrys, for your comments. I take your point and have tried to edit but as yet it has not responded. With regard to ID I was able to examine the specimen after photographing it to confirm.
No doubt about the ID...great photos!
The only way to get the ID as Eristalis pertinax (which fits with iSpot), is to enter it as a new ID; you cannot do it via edit. However, as you have an expert already agreed with the first ID, a new ID won't overrule that one. It might be best to leave it, but just be aware for future sightings.
Lat/Lng: 53.6701, -2.4673
OS grid ref: SD692193
On heather moorland about 300m altitude