Mike sent us this photo taken at Providence Farm on 14/05/19, and queried whether it was indeed a Brown Argus as they can be a very tricky species to identify without a clear sighting of the underside fore-wing. The Common Blue female with which this species is often confused, has an extra spot on the lower half of this wing which is missing in the Brown Argus. In Mike’s photo this area is just covered by the hind-wing making correct ID difficult.
However on balance we have decided it most probably is a Brown Argus.
There are other pointers towards correct ID which can be found on http://www.ukbutterflies.co.uk