Calling all armchair generals! Boudica's Last Stand.

[Renatus]

Good point about the IInd moving towards P, not vice versa, though.
Pretty fundamental and one I think Tacitus is clear-ish on.

There is no problem in Paulinus moving towards his expected reinforcements (whichever direction they were coming from). It makes sense militarily that he should link up with them as quickly as possible. Moreover, his scouts would be telling him that the enemy was moving up behind him, so he was being forced in that direction anyway. So far as Postumus is concerned, it indeed seems that he refused to move but, as time went on, he would be receiving a constant stream of increasingly angry orders demanding that he march out and, if he still refused, I would imagine that Paulinus would send an officer to relieve him of his command.

The difficulty with the northern route is that it would be a withdrawal into hostile territory. We know from Tacitus that Paulinus pressed through the midst of the enemy to reach London. If he was the cautious general we are told he was and knowing the hazards, it is unlikely that he would have gambled that he would be able to march back in that direction unmolested, particularly if he was accompanied by civilians whose protection he had assumed. Clearly, he had to make some hard choices but withdrawing into the territory of Cogidubnus, whose constant loyalty Tacitus was later to praise in the Agricola, seems the best option. There he could take the time he needed to consolidate his forces, the Second Legion coming along the Fosse Way, possibly troops from North Wales coming down Watling Street and the Fosse and maybe further forces from South Wales crossing the Severn at Gloucester and joining the Fosse Way at Cirencester. Spending that time in hostile country in the north would have rendered him constantly vulnerable to attack until he had assembled sufficient troops to deter any possible enemy assault.