My son and I saw the most amazing butterfly yesterday and found through your website that it was a purple emperor butterfly. Looking at their flighttime though, it would be too early.
Is there anything else out there being that size and colour, which I haven't spotted on your chart?
Can't think of anything offhand. This could be an escapee from some captive-bred stock (which may have emerged early), or an escapee from a butterfly farm. But Purple Emperors are quite distinctive in their habits (flying around the tops of oak trees, and only coming down to feed).
I'd say deffo a Purple Emperor. Oaken Wood/ Chiddingfold complex is between Guildford and Horsham and that's a prime site for Purple Emperors. Saw two there last Sunday on a Surrey BC branch walk. Maybe it was an early emergence due to the good weather.