A postcard from 1957. Rather nice images of London. A House of Commons postmark and a 3 penny purple stamp with a very young queen. And addressed to a Dr. John Mackey or MacKay on Carysfort Avenue in Blackrock County Dublin. No relation that I know of.
A link regarding the stamp explains that this stamp was known as one of the Wilding issues – they were based on photographs by a Dorothy Wilding.