Genuinely curious, what EV can give you a comfortable 300 mile with a good threshold, and charge in 15 minutes from a regular EV point?
As I said in the other reply, there's a paucity of EV chargers in the UK that are not along a major route, there aren't a large number of them, and they're rarely 'superchargers'.
The Tesla Model 3 has a real world range of 300 miles [0].
You want to give yourself a 50 mile buffer. So you need to add about 13kWh of energy along the route. That's like 8 minutes with a 100kW charger round it up to quarter hour.
285 miles on the highway isn't bad but that's only in mild weather. People in the North (American and Europe) live six months of the year in cold weather. Then they get 217 miles on the highway. In Europe this isn't even three hours of driving. And this is one of the best ranges on an EV under $70k.
It's a very common scenario for hundreds of millions of people. I'm really happy that your EV works for your family's use case. It doesn't work for mine.
As I said in the other reply, there's a paucity of EV chargers in the UK that are not along a major route, there aren't a large number of them, and they're rarely 'superchargers'.