I just finished chapter 18. Poor, poor John Chivery 😢 Dorrit really showed his beastly side in that interaction. And then to take his gift of the cigars, which Chivery could no doubt ill afford, and immediately give them away to his Footman 😡
ChessieFL beat me to it, I was going to refer to Merdle as Dickens version of Neil Woodford. I can see the Clenam, Sparkler and Dorrit wealth folding like a house of cards when he is inevitably unmasked as a charlatan who has been juggling a financial pyramid scheme. (Amy will no doubt be delighted to be transported back to gentile poverty though!)
I was also flummoxed by Floras visit to Dorrit in an attempt to track down Blandois, and also by Dorrit following this up with a visit to Mrs Clenham and Flintwinch. An action which seemed very out of character to me, as it placed him squarely in a house that was strongly connected with his poverty stricken past.
Although does he know Amy had once worked there, maybe not as he liked to pretend she was out partying every day and Flora only mentioned Amy working for her I think.
I do like Flora though, with her stream of consciousness way of speaking, she makes me laugh, as does Sparkler with his catch phrase of 'no nonsense about her' 
On the other hand I can't bear the way Dorrit speaks with all the humming and harring, or the hawking and sniffing of Pencks. Although this is probably because I'm mainly listening to the book, read by Julia Stephenson, and although she's a brilliant narrator she certainly doesn't shy away from hamming up these two and can 'hawk' and snort like a good'un when required to!
I don't think Fanny is happy at all Piggy, she cried with Amy when she decided to marry Sparkler and once she's established in her married home Dickens says:
“In her mind's eye, as she lounged there, surrounded by every luxurious accessory that wealth could obtain or invention devise, she saw the fair bosom that beat in unison with the exultation of her thoughts, competing with the bosom that had been famous so long, outshining it, and deposing it. Happy? Fanny must have been happy. No more wishing one's self dead now.”
I took from that, that she looked around and realised what a hollow victory she had won and what a miserable life she had carved out for herself with an imbecile of a husband. Although I can't but feel that Sparkler has the worst of the bargain here! He may be stupid but there's no malice in him (if some nonsense about him!) and I don't think the same can be said for Fanny!
I also want to push on with chapter 19 now to see what's coming!