I've been enjoying this although some of the cliches are irritating. Of course Lois would inevitably become pregnant from her first time having sex
I was surprised that there was no hint of disapprobation from anyone who knows about her pregnancy; in 1940 it would be a moral outrage for a young single woman to be pregnant, bringing shame on the family etc but it was very easily accepted by both Sean Bean and Lesley Manville's characters. Perhaps that will come as more people outside the family get to know about it. (I'm not saying it's the right way to react but it's how many/most people would have responded at the time so I'd like some period authenticity.)
I'm definitely most gripped by the Polish POV, Helen Hunt and her German neighbours - the scene with the father having joined the Nazi Party to protect Hilda was the most powerful of the whole series so far for me - and to a lesser extent Sean Bean and his relationship with his son and Lesley Manville warming to Jan. The little glance she gave over her shoulder to see if he'd heard/understood Sean Bean telling her that Lois was pregnant by Jan's brother-in-law was beautifully understated but spoke volumes about how she is coming to care about him.
I'm yet to gel with the Paris couple although the Jewish nurse made things more interesting last night, and Lois and Harry just irritate me - or at least, the contrived way their relationship operates. I presume the writers were trying to avoid the cliche of star-crossed lovers separated by class barriers but the reason they're apart / she's antagonistic towards him feels so manufactured and flimsy. She guessed he was involved with Kasia because he didn't mention her name?? She should be working at Bletchley with the ability to make leaps of reasoning like that.
I can usually handwave away the 'improbable distance' covered by the Polish fugitives because that sort of thing often doesn't register with me, but even I did a double take when I saw the trailer for next week and thought "how on earth has Kasia's brother ended up in the Normandy landings from his starting point???"
Sorry, that ended up a proper essay!