Bright orange butterflies

Observation - Bright orange butterflies - UK and Ireland. Description: Seen in Wendover Woods , Bucks, afternoon, bright orange butterflies moving very fast, not settling, larger than the average British butterfly. Lots of small dark spots on the upper wing. Moving too fast to get a better description. Weather was warm 28 d

Seen in Wendover Woods , Bucks, afternoon, bright orange butterflies moving very fast, not settling, larger than the average British butterfly. Lots of small dark spots on the upper wing. Moving too fast to get a better description.
Weather was warm 28 deg approx and sunny.Seemed to be concentrated along the cycle only trail between Icknield Way and Hale Lane.