Here is a butterfly I've been looking out for: the Brown Argus. Another tip-off from Jif that he had seen them in numbers in the Ickleford Meadows/Burymead Springs area in Hertfordshire.

 The Brown Argus is a small butterfly and hard to spot across a large expanse. The trick is to notice its flight pattern which is easier to perceive than trying to pick out a speck in the distance. Then fix your gaze on its flutterings till it lands. At that point the Argus is one of the easier butterflies to photograph because it obliges by remaining still while basking even when approaching very close with the camera.