This might be the right time to bring up the Mid-Atlantic or Transatlantic accent - which I had assumed was just the consequence of someone spending a bit of time on either side of the Atlantic.
Looking it up on Wikipediait appears it was actually a purposeful thing what that you were taught to do to accentuate your class / quality credentials, and was a mainstay of elitist prep schools and the theatre.
Exponents include Frasier Crane, Thurston and Lovey Howell III and Cruella de Ville.