Brown Argus in the garden

On Sunday 20th September, Jenny pointed out a mystery butterfly in the garden which I think is a Brown Argus, as it was all brown with orange spots above and on the forewing there were not spots beyond the median spot near the base of the wing. It flew onto the Lavender and several plants in the central bed and the one in the north- east part of the garden, although late it is still within the last week of the flight period of the adult.