Don't you think that Carmichael has been set up?
She is clearly the Chief Constable's apparent stooge and has been charged with emasculating AC-12, but she is not bent. Perhaps when she sees the scale and nature of corruption in Central she may realise that she has been set up and start working - against the prevailing climate - appropriately.
Definately.
Harrowby, for me, Carmichael at first appeared a possibility as 'H' - the cold, dismissive, shifty personality but then I started to think of her as a red herring. I do like your premise, though. Perhaps you should send your ideas to Jed Mercurio and he can muse on them - if he hasn't done so all ready.
The actor that played (plays possibly) Buckells, Nigel Boyle, was interviewed on BBC Breakfast this morning and was not giving anything away when asked if there will be another series. He was even asked if he was 'H' and side-tracked rather on the question. There are certainly openings that could allow it to happen. The series has been over a period of 10 years so Mercurio may have had enough.... who knows..