Marsh Fritillary

Walking up the hill in the warm sunshine yesterday we saw these lovely butterflies. But I could not not blip the Olympic Flame yesterday, so I was glad when we walked up the hill after lunch, to find these butterflies were about again (though in slightly fewer numbers). I think I've identified it correctly as a Marsh Fritillary - and I'm pretty sure it's the first time I've ever seen any of these before.