My understanding of how the wholesale price of electricity is determined is this:
At the moment, energy in the UK is traded on the wholesale market under 'marginal costing' which in the UK means one National price for electricity based on the price of the most costly generator that feeds the national grid. Invariably, this means that the cost of producing gas generated electricity dictates the wholesale price of electricity. So whilst renewable electricity might generate say 25%- 30% of the UK needs (and is multiple times cheaper than gas generated), nuclear another % (ditto), as soon as gas generated electricity is required on the grid, that dictates the price.
Now surely, given the massive brains at play in this government there is a way of unpicking that to ensure a true, more average cost of generation is charged. If that takes time then the model described above must be creating excess profit in those companies that generate electricity that could be levied as a windfall tax and used to mitigate things until they can sort out their pricing. Then the goal must be to get the UK to 100% self sufficiency utilising renewables and nuclear as quickly as we possible can.