I was writing to excellent reader Ann today, talking about the blog post I did on how we write about Regency-era slums and got to thinking about how I deal with 'class' in the books.
Do I consciously write about social class in these books?
Yep. I figger we all reveal our attitudes and beliefs unconsciously as we write ... so I might as well be aware I'm doing this and use it.

Take Lazarus.
Lazarus is motivated by resentment of the class that ruined his servant-girl mother and drove her into prostitution. This is the class to which his father belongs. The class Lazarus would enjoy if he'd been legitimate.
Lazarus runs an empire of violence and theft, in part, because he figures his minions are entitled to take what they want. The rich do. Why shouldn't the poor? He's self-educated and brilliant. He can't help but see the inequity in the laws of England. He ends up with great sympathy for the French Republican cause.
In his private life, his special ire is reserved for women of the privileged class who commit crimes that would land a servant girl in jail or send her to the gallows. Again, class motivates his actions.
Adrian's life journey is shaped by a desire to become 'a gentleman'. He walks, like Hans Christian Andersen's Little Mermaid, on sharp knives every step of the way. He finds himself, like Eliza Doolittle in My Fair Lady, unable to go back to what he was and yet unable to be comfortable with what he becomes.

Adrian originally admired the French Revolution, liking the leveling effect. Then ... an outtake from Forbidden Rose has him watching a tumbril take a family with teenage girls to the guillotine. We don't see the scene onstage, unfortunately, but that was a turning point of his life. It outraged him. He would never again be tempted by revolutionary violence. Years later, he rejects Napoleon as an ambitious opportunist. By that time, by 1799, Adrian is wholly committed to the British Service.
But he never rejects France's social reforms. Philosophically, Adrian is all for dismantling aristocratic privilege. He doesn't act on this because social equality is never offered to him as a viable choice in the 1789 to 1818 timeframe.
One reason Adrian gets along with Justine is they have no basic philosophical disagreement.

He plays at being a coachman or a laborer without assuming the interior life of one. He's an aristocrat inside. Born one. Schooled and trained as one.
More than that, Doyle's a practical man rather than an idealist. He believes a hierarchical society is inevitable, so he aims for a humane and workable system -- a fair, stable, well-run government with gradual change toward equality and social mobility.
The discussion Adrian and Doyle have at the beginning of Forbidden Rose is meant to show their different points of view. (This is prior to Hawker's disillusionment with the bloody side of revolution in France.)
[Doyle and Adrian approach the orangerie at the chateau. It's savagely destroyed.]
Hawker followed him, crunching glass into the gravel. “The boys in that stinking little village waited years to do this.”
“Did they?”
“They dreamed of it. They’d sit in those pig houses in the village with the shutters closed and the wind leaking in. They’d think about these fancy weeds up here, being coddled, all warm and happy behind glass. Down there,they were freezing in the dark. Up here, they were growing flowers.”
“That’s fixed, then. No more flowers.”
Out of the corner of his eye, he saw Hawker stoop and pick up a rock, draw back and throw. Glass fell with a thin, silver discord. The heroic revolutionaries of Voisemont had missed one pane. Destruction was now complete.
Justine is my most ideological character. In 1818 she's going through a period of disillusion, as idealists will. She's seen Napoleon fall. She's seen Paris turn away from the Revolution and accept the Royalists back in power. It'll be a few years before she gets her political fire back.

Justine's journey is one of rebuilding herself after absolute destruction. Part of this is reclaiming her place as an aristocrat. Though she's despised aristocrats, ironically, it's a measure of her complete healing when she can say,
“I will come to live with you in your great mansion and be a lady again. I will be a DeCabrillac, and face down the world if they make accusations. I will shake out your haughty mansion like an old rag and make it comfortable to live in.”
She becomes something she has fought against, because Adrian needs this from her. It's her gift to him.
Justine, too, is someone who doesn't buy into the class paradigm. She may claim her name and position, but I see her taking her aristocratic space cynically. She's gotten subtle in the Police Secrète. Give her a few more years and she'll be the Grande Dame of the Reform Movement, infiltrating the camp of the enemy, still fighting the good fight.