Sadly the pronunciation I have written as "haypenny" is on its way out in England as we no longer use the coin. It joins other odd pronuciations such as "tuppence" "thrupence" etc as we now use "two pee" and so on. Back in the day, my pocket money was a thruppenny bit, a strange yellowy twelve-sided coin.

I have just checked with my teen-aged son and he's never heard the "haypenny" pronunciation