Suspect PR12 exercise question may have got out of hand. As noted in post 46 - I can't see how you'd get anywhere near £1.2Bn to convert one ship. Unless you said to BAE - " the budgets £1Bn, how much will it cost (make sure you add on risk) to convert QEC".
Oh.....
Going back to B is a significant risk in itself. Overall this programme needs to be left alone to get on with it for a while. The build is going well, what is not going well is the continual vacillation by ministers, senior mil and CS and the determination by some in the media and elsewhere to portray the ships as disasters waiting to happen.