I also think that the characters tend to fall broadly into one of two categories that are quite important, in terms of how they think about the individual vs the group.
Lawrie and Tim love the idea of being 'brilliant eccentrics': Tim is very happy to take the highly individual status of 'Headmistress's Niece' and resents Me Auntie's preference for 'a great collective effort' at a number of points. Ginty, too, tends to fall into this category, as does Karen, just making her thing happen and pooh to the rest of us.
Nicola is more in this category than not, but this is tempered by the way that she, for example, nurtures even the less talented members of the form for the cricket team. Indeed, sport is often the way this plays out: Tim doesn't see the point of it, Lawrie wavers, Ginty much prefers swimming - solo effort in most cases, as in the diving cup - and flounders when asked to play for a team quite often. Nicola and Rowan ('always plays best on a losing side') can see the value of the collective in this context, though generally lean more toward the individualistic side. See also Ginty and Nicola in particular, with their hero-worship of Churchill and Nelson respectively.
And it's no surprise that both those men are more easily appropriated as heroes for someone on the right, politically, than the left. (AF doesn't say which party Anthony Merrick is an MP for, but she really doesn't need to, does she?). And Nicola's rueful reflection that the death penalty doesn't apply, even to vandals on a rural trainline, feels telling....
Being anti-individualism, possibly correlating with a more left-wing POV, is almost invariably coded negatively, except in team sports. Miss Keith's preference for collective effort over celebrating individual achievement, for example. Edwin Dodd's Guardian reading, too, feels deliberate. Pacifist, 'just boys', Ann never seeks recognition and it's hard to imagine her having a hero to worship. When cast as Mary, she seems to see this as a devotional act rather than .... acting. But just as Nick and Rowan can temper the impulse to individualism for the sake of the sports' team, so Ann is, paradoxically, willing to stand out alone when the rest of the Fifth decide to play to lose in the form cricket.