Observed down at beach level at Three Cliffs Bay, Gower, South Wales.
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I was a little worried about this as it didn't look right, but now you've pointed me in the right direction (again) I can see the id marks. The Dune Robberfly wasn't in my books!
I don't quite understand why you have said the above and then gone for Gooseberry Sawfly!?! ;)
My Flickr photos...
Shape is unmistakable. Philonicus.
Lat/Lng: 51.5697, -4.1094
OS grid ref: SS539877