Thanks - I had heard of them in North Norfolk but never round here (right on Norfolk/Suffolk border. Should i report it to anyone?

Sorry; only have underwing photo. SEEK app identifies this as purple emperor but wanted confirmation as that would be a new one for me round here (South Norfolk) (and I don't trust apps much!). Caught a glimose of upperwing as it flew off and it did look a lot like a female purple emperor.