I doubt that Alex Marwood and JK Rowling's backgrounds are entirely comparable. Rowling is in no way working class. She was the daughter of an army officer, an innately next-to-upper-class background in England, and while a broken home and an unwise first marriage did leave her in an accumulation of financial distress, her basic background had nothing to do with England's shattered working classes. Her detestation of the English class system (and the fact that she's gone to live permanently in Scotland) do not detract from that. You can see it in her clothes, in the way that she speaks, in the way that she stands and moves. She has been brought up to a certain kind of good taste and self-control. She is remarkably sensitive to the differences in status and social destination within what would seem from outside a solid social block; take for instance the way that, in The Cuckoo's Calling, the murderer has been essentially losing caste and power as compared to the spectacularly upwardly mobile victim - a sort of observation that only people who live within those realities would notice. I, with all my 37 years in England, might not have thought of that kind of underlying story structure; but you might find it in the excellent detective novels of the unarguably upper class Antonia Fraser, which I recommend if you haven't read them already. It's inside knowledge.