Sarah Hartley — Miss Hartley, in the manner of all primary-school teachers in 1995 — is a class teacher at Stepping Stones Primary. She is referenced in Cambion only in Daniel Marsden’s interior reflection in Chapter Eight: Sunday Words, in three quick passes. She does not appear in any scene. She has no spoken lines.
The three references add up, in Daniel’s mind, to a single half-formed observation about Robert Knight. First, the body-memory simile for his own anxiety: his hands were shaking — proper shaking, like when Miss Hartley called on him and he hadn’t done the homework. Second, the moment that becomes one of the load-bearing pieces of evidence in Daniel’s investigation: The way Miss Hartley struggled to lift him for the school photo, even though Robert was smaller than Adam. Third, the texture: the strange symbols in his father’s files looked old. Medieval, maybe, like the illuminated manuscripts Miss Hartley had shown them in History. Three small classroom moments. Three pieces of the same growing realisation.
Miss Hartley herself was, as far as the manuscript shows, doing her job. She called on the children in turn. She struggled, briefly, with a slight boy at a school photo and didn’t quite know why. She showed her class illuminated manuscripts because she liked them and thought the children might too. None of these things were unusual to her. All three of them now sit in Daniel Marsden’s notes about Robert Knight.