I'm finding addressing characters by titles continues to frustrate.
Namely because it's so much easier on the reader to refer to a character by a single name (usually their first) along with any title, as necessary. It's a single pronoun for the reader to remember and refer to. It allows for a fundamental consistency throughout the narrative. This is especially important where a number of characters may be named.
But technically titles should be assigned by family name or region, which immediately results in multiple pronouns being assigned to the character, and different frames of reference being used. Which is all fine and expected in historical fiction where the characters and pronouns will be more familiar.
For example: Andrew Windsor, Duke of York.
Who can variably be referred to as Andrew, Andrew Windsor, Windsor, The Duke, Duke of York, York, (and, of course, Prince Andrew) - according to who is addressing him. In most instances, the pronouns are familiar enough to (at least a British) reader that confusion will be minimal - even though there are 3 pronouns and 6 different potential ways of referring to them.
But this becomes problematic in fantasy where the first name, family name, and region, will be all completely new and unfamiliar pronouns. Keeping to just one form of reference/address just isn't realistic.
For example: Brandan, Brandan Barrickson, Barrickson, The Duke, Duke of Framley, Framley - are all these the same person, or different people being referred to? Any sane reader will be forced to stop and think about it, and face potential confusion - especially if there are multiple male members in the same family, let alone other characters with the same first name (Andrew is hardly uncommon, either).
In which case, I'm now thinking I should break all convention when it comes to issues of peerage - and lose a degree of historical realism - simply to have a compromise that works for the best interests of the reader.
That means all characters referred to by their first name, or title + first name, with any reference to family names or regions pushed into the background - referred to when necessary, but never used in such a way as to cause confusion as to which character is being referred to.
[EDIT - A check check suggests this may be the approach GRRM took, but I'd have to re-read with an eye on that. EDIT 2: In fact, a quick search of the ebook suggests he avoid common titles entirely, ie, duke, earl, viscount, baron, etc]