"he UK grid has a generating capacity, flat out, of ~ 96GW so with 8760 hours in a year it could manage 840TWh if everything ran flat-out 24/7. Annual consumption is around 360TWh, so about 41% of that."
You haven't included a deduction for all of the power used in the refining process to make petrol and diesel. Just the electricity alone in one gallon of petrol will allow the Chevy Bolt to go 30 miles.
I do acknowledge that petroleum fuels are one of the densest forms of energy storage. The downside is they are a finite resource and very dirty to obtain and use. Coal and natural gas aren't totally clean and there are issues with currently used reactor designs but, overall, the electrical grid has a much better chance of getting environmentally cleaner where petroleum fuels have a near zero percent chance. Right now, batteries are the best portable method available for storing and transporting power. People talk about Hydrogen, but it's horribly inefficient to produce and to achieve a large enough energy density for a portable application, it has to be put in tank pressurized to 700 bar.
I can't see how a car charger would require training. It's not like it can spill from the end of the plug if you don't secure it properly or explode if you drive off with it still plugged into the car (EV's won't allow you to shift into drive with a cable plugged in). Most people will be using non-DC fast chargers for the bulk of their charging needs and people in city centers that have no place to charge won't be purchasing EV's. Relying on fast chargers is expensive and time consuming. If you don't find one available to just pull up and charge, you might be waiting 30 minutes for your turn. If there is already somebody waiting ahead of you, it could be over an hour. That's a distinct possibility in areas where most of the housing does not have private parking. Maybe that will lead to a gradual reduction in housing density. One can only hope.