I can't believe I'm saying this but John Simm is woefully bad in this. He's as wooden as a plank. Playing a character lacking in surface emotion just doesn't suit him. Richie Campbell is awful as well. There's no spark between them. At least there are two actors in this with a bit of life in them, Zoe Tapper and Craig Parkinson.
Adding to that, the supporting acting and plots are so bad it's like a spoof. But unlike McDonald and Dodds which is equally dire, but slightly tongue in cheek with good rapport between the lead characters (and hence watchable) Grace takes itself completely seriously. It's an embarrassment. I can't understand how John Simm is happy to continue being in this drama. He's never been a money chaser. He must have signed a golden handshake.
As I said, I can't believe I'm saying this about John Simm as I've seen nearly all his work and his performance usually blows me away. Maybe series 3 will be better.