Not sure we have signed for the hardware, probably more like an MoU at this stage.
Orca - I doubt very much whether any significant sum has been spent on de-STOVL-ing either QE or PoW. What will have been done is a lot of initial scoping studies, with manhour totals in the tens of thousands, hundred at the outside. Cost incurred £5-10M tops.
However, that kind of reinforces the point that the £1.8Bn "conversion" cost is some sort of fantasy. I'll say it again until my head drops off - if the hardware is £500M (which it is), then £1.3Bn in manpower rates now would allow you to build Illustrious in her entirety thirty years ago! They (and I don't think it's BAES here) are making it up, but as it suits some agendas, that's the number.
Clunk.....