We saw it; I quite enjoyed it, Rodo, whilst Mrs O was a bit more ho-hum.
It was slightly difficult to follow the accents (could have done without the background music at times), but in contrast the plot was easy to follow, Mrs O (on the couch) predicting many of the developments before they happened!
Nothing wrong in that ....
And yes, it was set in a dark and dreary, rainy 1950's or 60's Dublin - effectively it was a "noir" but that was quite acceptable in context.
Gabriel Byrne extremely well cast, as Osc said. We'd certainly be watching the rest of the series.
I did wonder once or twice if "Crimea Street" was the same set as used in "Ripper Street" ......
Overall, from an Irish drama point of view, I'd say better than "Jack Taylor", not as good as "Single-Handed" - I don't know if you'd agree, Osc ....