This looked "unusual". Any id appreciated.
All photos added. The light silvery grey colour was what drew my attention to it.
No interactions present.
Looks like Dexia rustica in Chinery's guide, but I am not confident enough to offer this as a revision.
It's certainly a Tachinid - can you add some more photos to this observation please for more views.
Tachinid Recording Scheme
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More photos have been added. Thanks for id of tachinid added 28/4/11.
Lat/Lng: 51.2, -0.5
OS grid ref: TQ0951