Board Thread:The Panopticon/@comment-1350697-20160118150156/@comment-5918438-20160123064436

She is consistently referred to in credits (as well as book titles) and by the Doctor as Ashildr, but never remembers this name. T:CHAR NAMES means we need to make sure to use the most common name, often the one in credits.

There's also a purely technical aspect: at two characters, readers can't search for it in the search bar, and it won't come up in autosuggest. As a general rule, pages need at least 3 characters, and this particular page is one which is visited a lot by readers due to her extensive involvement in the last series. It would simply make no sense to have her unsearchable.