I'll start by saying I like Rebecca Gibney. She's a capable actress I've seen in more than a few Australian drama's.
"Halifax: Retribution" offers her the opportunity to hand in yet another strong performance. Its a by the numbers crime drama that works well enough. It offer's up decent doses of excitement, intrigue and a somewhat predictable twist, that should keep the viewer coming back for more.
What I was not so impressed by, was the pro establishment boot polishing. Painting those who opposed the Five Eyes and surveillance state, as unstable and murderous. Most activists are peaceful and the Five Eyes alliance is, not unreasonably, the subject of very legitimate criticism. As is any surveillance state, in general.
For me, this rather obvious pitch for "keep you safe, sticky beaking" detracted from this series and I'm voting it down because of it.
In summary, competently done with a strong cast. That said as I seem to find myself saying a lot these days I come to entertainment to be entertained. I don't need or want possible political messages or social engineering in the mix.
5/10.