Look what I found sitting on the fence

Now most years it wouldn't have been remarkable to find a small tortoiseshell in the garden as they are usually the most prolific of the coloured butterflies, but not this year when I've seen less than a handful.  I can't remember if I saw one earlier in the year (I have photographed them in March in the past).  I was attracted to the four white butterflies that were `dancing' in the air around the garden, which initially I thought were small whites, but now I've looked more closely at both the markings and my reference book I think this is a female large white.