In an old episode of The West Wing, a British Ambassador is referred to as "Lord John Marbury". Ignoring that once he became Ambassador he'd be Mr Ambassador, what are the possible correct addresses?
My reasoning is that a friend criticised a newspaper which used the form "Lord Firstname Secondname" saying it's supposed to be "Firstname Lord Secondname".
For example, with Lord Coe — or Seb Coe —, his wife is said to be "Carole, Lady Coe", but assume that's just the different names options (as there's a comma)? It's not explicitly stated that there's a correct way to use his (or her) full name, that I can find online.
I tried using the West Wing episode as an example, but they pointed out that it's an American show. Indeed they get other details wrong, like saying two Commonwealth ambassadors met (when ambassadors of Commonwealth countries are referred to as High Commissioners when dealing with each other).