Not a bad summary of the issues from a recent briefing in the Parliament library. The downloadable PDF sums up some of the issues as recently publicised in the press.
The F-35 Joint Strike Fighter - Commons Library Standard Note - UK Parliament
Of note is that in January 2011 there was a real possibility that the B would be axed due to technical issues so at the time of the reversal in some ways it is understandable that they jumped to C, rather than hold the nerve.
The decision on what cat and trap system was not due until late 2012 and that extra training costs of the C may negate the perceived 25% through life cost advantage over the B.
The government wont even set a firm in service date until after 2013 and the procurement of all types has been delayed.
All in all a complete balls up. But if the decisions have not been made yet on conversion costs this whole process may just be an excuse to delay the problem even more to avoid having to purchase the long lead items. I know there was mention of penalty payments meaning The government said it would cost more to cancel, but with POW only just started, and potential £1 billion plus to convert, is there any window for this lot to pull the plug on POW altogether? Would the penalty be less than the conversion cost allowing then to "save" the taxpayer money, then just press on with QE with a vague promise of a tiny buy of B down the line, "well the french manage with just one carrier"?? Unlikely but I wouldn't put anything passed them, they were quite happy to can £3 billion worth of Nimrod and a perfectly good Harrier fleet. (and who cares if those nasty scots don't have a ship to build after they vote independence in 2014)
The problem is there is not an ounce of honesty amongst them, no long term plan and just an overwhelming desire to build a war chest to win votes in 2015.