BEIS Capacity Projections - are they Serious about how Little Firm Supply we Need?

Oh dear, even worse than a graph - a table!
What does it tell us?
BEIS, the Government department in UK responsible for Business, Energy and Industrial Strategy, projects how much electricity capacity they think we will need over the next 20 years.
Where do we start to dissect this and make sense of it?
First, there is a 30% increase over the period in total capacity, from 110 to 142GW.
But this includes renewables, which are almost all intermittent, and can not be relied upon to produce electricity at peak times.
So the peak firm supply capacity, without allowing for any downtime for power station maintenance or breakdown during the winter months,, is much less.
In fact , it goes from 70GW at the moment to 74GW in 2035.
42% (31GW) of this firm capacity is storage and interconnectors, i.e. electricity from abroad, arriving by undersea cables.
So we will have only 43GW of firm generation capacity in this country, considerably less than our current peak demand of around 50GW.
Fine you may say, we are getting more efficient in our use of electricity, and we are - at least some of the readers of this blog! - shifting when we use electricity away from peak times.
But we also have an intention to phase out petrol and diesel cars by 2040- and each new electric car requires about 3kW of additional capacity - that's 90 GW for 30 million vehicles.
Should electric vehicles be allowed to charge at all outside trough demand times, say midnight to 6am?
 They are at the moment...