But that expensive guaranteed price still wasn't enough to cover the actual costs and the EdF CFO resigned in protest.

Once that became too obvious to deny, after the French government had renationalised EdF, they were begging the UK government to give them more money, possibly buried in the contract for the second plant build.

For that build they stopped using CFD, a financial instrument designed for nuclear but which has massively helped renewables, be ause it couldn't hide the nuclear cost overruns. They're now charging electricity users in advance for the nuclear they are going to build with no guarantee of eventual costs.