The Postman Butterfly (Heliconius melpomene) is one of Heliconiine butterflies found in South America. Several species in the genus have very similar markings and looks and are difficult to distinguish. I saw this one at the RHS Wisley Butterfly Event last February.
Settings: F/4 1/250sec +EC1.67 ISO125 165mm handheld
Many thanks for your kind comments & clicks on the Wisley Exotica flower - have contacted Wisley to ask for an ID