I arrived around 10:45 to find a large group of butterfly enthusiasts all looking down at something on the main track not 50 m from the car park. Sure enough it proved to be a magnificent Purple Emperor but it was in the shade, unlike previously when I have always seen them in the sun. So unfortunately there was no chance to attempt to get a photo showing the iridescent purple on both wings (something that has eluded me in the past). Also with so many people around it wasn't surprising that before long it took off and disappeared along the path.
Purple Emperor - showing a hint of purple on the right wing, even in the deep shade.
Thereafter, the butterfly group departed along the path, leaving a small number of keen watchers, including Ewan, Winston and Stephen. However as the morning wore on nobody could find any more Emperors - with some speculating that it was too hot for them, which might explain why even when they showed, they were sticking to the shade. Also it seems their short season is probably coming to an end - as they have been on the wing for a whole 2 weeks!
Remaining interested centered around a path-side Oak tree just a little further down the path that held an amazing number of Purple Hairstreaks, some of which were coming low down, well within camera range. Not an easy subject though as they twisted and turned just frequently enough to hamper photography.