weak hollywood remake of classic bbc series

Apart from everything else jedburghs introduction to craven seemed much too blunt - his job was to cover up for Northmoor, however straight from the off he does the immediate opposite?
Plus he and craven where portrayed as far too clever by half: spouting Latin and using classical analogies and metaphors.
At what point was craven poisoned? Once he knew his daughter had been you would have thought craven would be on guard? Plus why poison him? It seems so ott and slow. Also it would be so much more suspicious and raise questions?
When jedburgh lowers his gun was it necessary for the young officer to shoot him? Yes I understand it was "suicide by cop" as he had a terminal disease but for the officer to then shoot him with no efforts to persuade him to drop his weapon seemed off to me? Maybe its sadly the nature of things in the US where often the first and only option considered is extreme force and the use of firearms - unlike here in the UK where a more measured approach and policing by consent is undertaken?
One assumes by his rank of captain that jedburgh had at one point reached that rank in the royal marines or sbs/sas and had been either seconded to the US or had gone over to the dark side after retiring from British military service?