I've copied the distribution in Derbyshire from a short article published by Ken Orpe on the East Midlands Butterfly Conservation web site.
|Wall Brown in 2000 recorded in 110 tetrads|
|Wall Brown in 2008 recorded in 19 tetrads|
|Wall Brown in 2013 recorded in 54 tetrads|
'During 2014, only 10 of the 59 sites that had transects carried out in the County had sightings of this species and the overall total was just 43 individuals, half of which were seen at the Clough Wood site.'
Which shows how important Clough Wood has been for the butterfly in Derbyshire.