I just read "Black Moon," "Four Swans" and "the Angry Tide" then I watched Oldark Season 2 and they did a closer adaption of the books than season one of Newdark did with "Ross Poldark" and "Demelza".
Why that was so shocking was in season 1 Oldark played pretty fast and loose with the material in the books. It makes me wonder if Winston Graham played hardball and refused to give them the rights to the books unless they stuck to the books.
And it's really going to be interesting after this season when Aidan Turner and Eleanor Tomlinson are going to have to play middle-aged Ross and Demelza with grown children.
IMO, if Newdark gets that far, I think they'll be fine to do what other dramas are doing with big time skips, like Outlander and Vikings, minimal aging and hiring actors in their late teens or early 20s to play their children.
The jury is out about that one. We don't know if the series will continue past book 7.