It's not that PE is never seen in S Devon, there are a handful of sighting records there, it's just that its so rare there that we look for another explanation first. I usually go for the trope that if there are two explanations, one involving something very rare and one involving something reasonably common, it is close to certain to be the the latter. Thus the person who was strongly asserting they had seen a golden oriole out of season and in the wrong place was eventually persuaded it was a green woodpecker. But if you look under Camberwell Beauty it says "rare migrant", but I've seen Camberwell Beauty a couple of times; after all there's really no mistaking it. It's been a funny year for butterflies, the obligate early breeders suffered badly, but others have thrived.