Hmmmm...,. So you're suggesting that the D width used for the Marlows sold on Ralph Lauren's US website may, in fact, be a UK D width? I've seen some people suggest and refute that on here before. I don't have a pair in my possession to look and see if they put a number (4 or 5) inside as well.
This is my experience, as Lauren said Us D is certainly narrower than Uk E.
But fit can vary from case to case.