I listened to the 1st episode and continued with this episode. I was a Cold War Warrior, serving in the British Army 1966-1991, and I am of the view the scenario developed too rapidly. Before Russia began any physical deployment (which costs a lot of money), there would have been much more simple sabotage. One of my specialties was NBC Warfare - Nuclear, Chemical and Biological Warfare, with Biological being the simplest, cheapest and most rapid acting tools. Think siege warfare of several centuries ago, firing dead and rotting animal carcasses into besieged sites. The moden version of that is likely to be Spetsnaz agents, doing things such as walking around a reservoir and dropping in minute quantities of biological agents. The infected water - perhaps supplying parts of London, but more likely garrison/port towns such as Portsmouth etc - would rapidly debilitate large numbers of people and miitary troops and personnel with afflictions such as dysentry, influenza etc.. An unreal rush to physical attack.