I'm halfway through s2 at the moment but there's something that's been bugging me other than the difficulties involved in not drooling too much while watching
So there's the four sons - Arthur, Tommy, John and Finn. Their father clearly pissed off a long time ago. Their mother died at some unknown point, I kind of assumed when the youngest boy was born, and Polly raised the boys pretty much as her own.
There's all the talk about how the boys changed during the war, and they sort of give the impression that after coming back from the war it was Tommy, who'd become a Sgt Major, who took control of the gang, rather than Arthur, the eldest. But the war was several years long, and it seems they fought for a few years, leaving Polly running the shop while the men were away.
So... who ran the gang before that? 
I know I'm probably over thinking something in a drama that's hardly up there for its historical accuracy, but still - didn't this bug anyone else?