This show on Prime is apparently Season 3 of "A Very English Scandal" instead of its own title called "A Very Royal Scandal" as it is advertised. I searched for "Royal" and was at a loss. I checked the date, and it should be available, but it wasn't there. Just for fun, I selected the Hugh Grant series and went to Season 3, and there it was!
So far, only through one episode, but it's really well done (assuming you know a bit about the story in advance). It's hard to write a review this long without giving anything away. I guess I'll add by saying it's odd they chose to start this miniseries where they did, an interview that's about to happen with no context as to why the interviewer is so flummoxed.
Happy viewing! Hope others find this useful in locating the show.