A Modest Proposal
The REAL challenge is not where to place the chargers, it's where on Earth to get all the extra electricity generation needed, and baseload rather than fickle wind and solar.
That's a correct albeit unpopular assessment.
So here's what you do ...
Put the effort to site and build charge points out for public bid. If you require the successful bidder to have actual experience in siting and provisioning charge points, very likely the only acceptable bid will be from Tesla. Will Elon bid? Almost for sure. The man has never seen a subsidy he didn't like. Can he do the job? Almost for sure he can. And since this is something his company has done reasonably well before, he'll probably do a good job.
But Musk is going to point out (as you have) that the chargers require adequate power. And I imagine he will suggest huge banks of solar panels and humongous backup batteries. All of which he can sell you.
But England is way too far North to power its transportation grid with solar energy especially in Winter? Of course it is. Any teenager who has mastered basic arithmetic and trigonometry can work that out in a few hours. But that's not Elon's problem. It's yours. It just means that you need a LOT of solar panels and an enormous number of batteries. And it'll cost a bloody fortune? You bet. Maybe you should have looked at the invoice for zero emissions before you signed on.
I'm not an Elon Musk fan BTW, but as I see it, he's the about only guy with any realistic chance of bailing you out of the mess your folks are creating. Like they say, "Any port in a storm."
What's the alternative? Nuclear power I suppose. But humanity has managed to dink around for half a century without coming up with an inexpensive, easily replicated, safe, nuclear reactor design that does not easily support nuclear proliferation. Perhaps you folks should consider holding off on saving the planet until you have a proper toolset?