Modern civilization is highly interlinked. Even a small problem can cascade to big things via supply chain domino effect.

In OP's hypothetical scenario, bicycles would be best bet.

We saw first-hand during the Plandemic how globalisation has made much of the industrialised world dangerously dependent upon each other, and often some very scarce products / natural resources (e.g. rare Earth minerals), many of which are controlled by some rather nasty regimes or just a handful of nations / companies.

It should've been a global wake-up call to everyone (people and nations) to become more self-sufficient and less reliant on others, especially less friendly, less stable, more corrupt and far flung nations and powerful globalist corporates who appear to have little in the way of ethics / principles that most decent people share.

I would note that bicycles need to be maintain just as cars do - cleaning, lubrication, spare parts like chains, cables, brakes and inner tubes/tyres, just like cars, dependent upon usage. Plus you will need to wash yourself and clothes more often if you use a bicycle regularly.

Still a lot cheaper than for a car, but products still need to come from somewhere, and most these days does come from abroad.

Last year, I spent around £1100 on my car (only 1450 miles driven) all told. I cycled (leisure only) around 2500 miles and I spent around (averaging out sunk costs of products bought that will last more than a year) £150 on it and related items.

Whilst I could do grocery shopping using it, it wouldn't be that practical, given I'd have to have a lot more trips (and in poor weather - which could be dangerous), which probably would be more costly for the actual purchases. Plus, of course, I wouldn't be able to buy large items and get them home like I would with access to a car, although very large ones still have to be delivered even now.

One of the problems we face in the modern era is how much of our lives depends on others and technology, especially that is remote from our home and not within easy reach via walking or, at best, a bicycle.

Plus so much we take for granted is deliberately designed to have a relatively short lifespan and little generic parts used, in order to guarantee future business, whether via expensive repairs (if even possible / economically viable) or being forced to replace a whole product just because one or two small (but integrated) components fail.

Other than rust protection, I doubt if few cars made over the last 10 years would be economically viable than those before. Cars, like many products, used to be economically repairable, including well out of their warranty period or the 10-year legal period spares have to be produced after a vehicle goes out of production.

I can't see that continuing, with cars getting like mobile phones, only a lot more expensive and the (new cars) purview of the wealthy only.

Your travel arrangments would be the last thing to worry about.

Having seen the behaviour, the violence and thuggery on a black friday sale or over the last must have toy for Christmas, could you imagine what they'd do to you to get your food and essentials and if you happened to live somewhere that could be defended they'd come mob handed and you'd either surrender and leave, if they let you, or fight it out and hope to survive.

The UK has ~2 weeks reserves of gas, ~2 months reserves of oil, and (I believe) ~3 months reserves of food (probably very basic).

A collapse of global production and therefore zero future oil imports would probably lead to rationing within 1 week, and imposition of martial law within 4 weeks to eke out dwindling supplies for food, law and order, water and sewage treatment etc.

Power cuts would become widespread. Food reserves would be exhausted within a few months as fuel shortages limit imports, storage and distribution. All EVs would be requisition for critical services.

Law and order would break down within a week or two. Anyone with evidence of personal advantage would be set upon by mobs. Either mob rule (might is right), or military rule would dominate.

The least of your worries would be "how do I get around". Higher up the priority list would be avoiding personal violence and getting enough food to avoid starvation.

Well I could carry on as before, charging the EV using the solar panels.

That is, until some enterprising 'blokes' nicks them right off your roof whilst another two threaten you and yours with deadly violence if you try to intervene or call the Police, not that they'd be around to help anyway in such times.

And what happens even if you are lucky to avoid that, when the PV panels and/or related equipment go wrong / fail permanently (end-of life) or don't provide sufficient power for your needs, especially if / when there's no grid-based leccy?

Most PV systems for houses (never mind flats, which have far less roof space for them per property) won't be able to continually sustain usage for the home and an EV. You'd be lucky to get a day or two's usage (backup to a battery wall) out of them over a week in summer, and far less in winter when there's a lot less sunlight available and much greater power needs, especially if the home uses electricity for heating and hot water generation.

The only alternative would be (as you probably were aware of during the 'problem period' over the last 5 years) cutting down local trees for firewood - obviously not a sustainable (and I mean use of the resource compare to the population size) method over more than a few weeks / months in one year only.

Plus, where would you get spare parts and maintenance done for your EV when needed? I don't recall seeing any branches of Halfords or useable car repair shops in any dystopian future films like Mad Max.

Maybe that’s why after seeing what happened in Spain earlier this year when the power cuts caused by their governments move towards net zero has alerted many people in this country to take some initial steps to avert a similar but likely event here.

Keeping at least £500 in cash , a stack of bottled water , emergency rations similar to what the armed. Forces use, a small generator or at least a backup supply for the wi Fi which nowadays powers the land line unless you avoided sensibly the switch over to fibre and a supply of essential medication .

Failing that a move to South Island New Zealand may be a good move for those who can afford it like Noel Edmunds !

You would want to be quite a long way away, and upwind from the most likely sources of an EMP (i.e. thermonuclear detonations) otherwise you wont be needing your car.

In other individually probably less likely (and less apocalyptic) apocalyptic scenarious, a car might be of some limited use, BUT I remember in John Wyndhams "The Death of Grass" his characters decided to proceed on foot across starving Britain to their place of refuge because they were less likely to run into an ambush that way.

Struck me as tactically plausible. They did have guns though, which most Brits dont have access to.