And how many are working combined with how many have a sufficient connection to the grid to power all the chargers in the local cluster if all are being used at once (for reference see the hassle a recent pair of youtubers went through when doing a ICE vs EV "race" from John-o-Groats to Land's end[0][1].

Spoiler alert, most chargers were broken or had queues to use (so an hour to wait even before you got your '20 mins') or were gimped into low power delivery because all of the points were in use and the connection to the grid was only enough to serve one car at full power.

I'm not saying this all charging stations all over the country, all times of the year (this was on a weekend of a half term holiday) but even as a snapshot of where the UK is in getting the infrastructure up to speed, we are a long way behind the demand curve, and that's before you take into account all the people who haven't bought into EV's yet because of their reliance on public charging infrastructure (due to not living in a house with a driveway etc) which has been shown now to actually cost more per mile than an efficient ICE car in Diesel/Petrol when using public charging networks.

(In the video referenced above, Lee had to resort to using more expensive charging locations (due to unavailability of the planned ones for reasons listed above) and the final charging bill for the distance of the journey was nearly £260. The ICE (diesel) was £122[2]
The usual cry against the public charging situation is "should have bought a tesla" and "Home charging balances that out"

1. We don't have a monoculture of cars, not everyone wants or even LIKES Teslas
2. Home charging is fine if you happen to live in a house where that's viable, which is AFAIK less than 50% of householdes in the UK.
3. The home charging cost is typically (dependent on the tariff deal you have) anywhere from 8p to 30p per KWh. range varies on model, but the best EV's have an upper end in ideal conditions of around 4 miles/KWh so between 2-7.5p per mile in the Lands end run video, Geoff got around 13p per mile (mainly not using motorway filling stations so avoiding excessive costs.)
Since an EV is still a premium/luxury/early adopter product, the cost premium is usually at least £10000 more than an equivalent ICE car. In order to recoup the cost premium you need to do 90000 and 150000 miles before it earns it's difference back. For most cars (in the UK due to attrition from road conditions or other drivers inability to not write your car off) that's in excess of the operational life of the car (that being said both the cars in my household are north of those numbers, but they are definitely in a minority) let alone that fact that people now are all too keen to keep a car that long.
The numbers made sense a few years ago but until the prices start getting more realistic for ordinary people it's a gamble (Oh and now EVs are more expensive to insure too, further offsetting any running cost advantage)

Right now the only argument (for me at least - and I do have a driveway) for an EV is the environmental one but the production of them is far from perfect too (but it's still early days so who knows) There are much bigger wins to be had in industry and travel than getting me into an EV (like improving public transport to the point that it actually becomes more viable for starters)this all sounds like I'm anti EV and anti public transport, but I actually WANT to like them both (I never needed a car when I lived in Hamburg with an excellent interconnected public transport system)