One of my favorites is Marylebone. Just about every variant seems acceptable except Mary-le-bone.

As McGrath said It breaks down with incomers. I now live in Chesham. I have had my pronunciation corrected in other parts of the county to Chess-am or Chezzum but I never hear either locally although I have heard recordings of local people using those pronunciations in the 1950s

One the other hand a local will seldom refer to Rickmansworth as anything except Ricky.

Back to the original in Oxford the college and the street are "Maudlin" but I believe that the suburban Magdelen Road is pronounced as written.