I think one reason that Mitchell painted Jason's schoolteachers as extremely nasty is so they would later act as a contrast to the person who turns out to be a much more better teacher than any of the school teachers: Madame Commelynck. Her advice in regards to poetry, literature, and language have immediate impact on Stephen (translating that French book for example). Furthermore, like Hugo, she acts as a character that shows Stephen that its OK to write poems. Hugo does it by liking poetry *and* being cool. Madame Commelynck simple says screw everyone else, if they think you're gay for writing poems they're bafoons.
She's an interesting character because, while she seems very cultured and knowledgeable, when she started talking about living next to Charlie Chaplin and all those other famous people I felt a hint that she might not really be everything she makes herself out to be. I don't really have any concrete evidence... the whole situation just seems really weird. And then, to make things weirder, she gets extradited. Are you kidding me? Mitchell is totally playing with us.
"Hey, here's this cool character who's helping Jason with his poetry and overcome his inhibitions aaaaand she's extradited"
All in all, Solarium is kind of a weird chapter. We'll have to see how Jason responds to his short experience with a great teacher and how this effects his membership with the Spooks