I also binge watched. Stuff and nonsense, but quite enjoyable stuff and nonsense. The reason why she doesn't flinch when her partner is shot becomes clear - i thought it was clear by episode 2? The family believe she is a disgraced cop, her bogus history easily accessible for them to check. The murdered guy being the Home Sec's son is purely coincidental. The men may sound the same because they are all from the same neck of the woods. As for all looking the same, i suggest a trip to Specsavers :-))