Name of British Spy Mini-Series Around/Before 2012

I saw a mini-series around 2012 (on American TV) that I'm trying to remember the name of. I only remember a few scenes from it. Here's the best I can recall, and it may not all be completely accurate:
1. It was only one season, maybe 5 or 6 episodes.
2. There were two male "spies" as main characters, both middle aged. I recall one of the things they did was placing listening devices in a family's house, to eavesdrop on the woman.
3. One of the spies set up a rifle with telescope on a table in a second story flat. (I think it was a table on top of another table, to be really high up.) He set the tables up far from the window in the back of the room so no one would see him from the street. I don't recall he ever fired the gun, it was just to use the telescope to surveil something across the street.
4. One of the spies had established an alter-ego presence in Dublin. He traveled there periodically to show his face and keep up this false identity. When he got out of the spy trade, he was going to move there and disappear off the radar screen under this different name.
5. There was a big fire at the end of the movie, in this spy's Dublin location. I think the main spy perished in the fire.

Really hope someone can recognize the series from these few facts. I've searched all the Best Spy film listings I can find, and can't find it. Thank you.