Scrap
Surely there must be a market for them with buyers living in areas outside these controlled zones.
I've got 2 classics with a combined age of 58 years, but am fortunate enough to live well outside any such restricted areas.
Indeed. It's very much a "swings and roundabouts" situation. City dwellers get much better public services than rural dwellers. They get cheaper fuel, on average, they get public transport and they don't have to travel as far to get what they need, even if they choose not to use the public transport. However, they have less space. Parking is often a problem, they have lousy air quality and pay more for their houses, etc. I have a 33 year old car, and I accept that it wouldn't be a good idea to take it into a city centre.
Electric vehicles are, indeed, expensive right now, but the prices are coming down all the time. If you look at what ICE cars cost (say) 20 years after they started to emerge on to the market, electric vehicles are an absolute bargain by comparison! The problem is that people have started to just expect access to a private car as a fundamental human right, whereas when ICE cars were first introduced, they were only a luxury for the very rich. We need more people to buy electric cars to "prime" the second hand market, so that prices start to come down and ultimately, the people who buy £500 "bangers" now, will be able to buy £500 electric "bangers" in (say) 5 years time. What we then need, is for the garage trade to get to grips with working on EVs and for the non-genuine spares manufacturers to gear-up to produce affordable spares. EVs have quite a few "wins" already, when it comes to running and maintenance costs, but the batteries are cripplingly expensive. I have a cordless drill, for which I've recently bought a replacement battery. Chances are, it won't be as good as a genuine one, but it was a fraction of the price. I'm pretty confident the same will happen with EVs. (And, of course, in the meantime, if someone cracks the problems associated with hydrogen, we could, perhaps, even get to keep our ICE vehicles!