Watched the first episode tonight.
Thought it was very good actually. You can't deny, the cast is stellar. Never dragged, and definitely left me wanting more. I don't know how to explain it properly, but it's filmed really nicely and a treat to look at in places. I think that's called cinematography. It was also a blast from my past as I used to walk through that big hall in the FCO every day when I worked there. It's called the Locarno suite. Looks a bit plain now compared to when I was there. The ornateness of it appears to have been stripped.
Will undoubtedly watch the complete series.