You are forgetting Peter that in UK many homes, the domestic supply is only rated at 60Amps. A friend who lives nearby had his supply upgraded recently as he is going to be completely electric for heating, cooking and is having a 32Amp charger installed as well. While he is knowledgeable enough not to put too much on at once, the next owner may not be and with everything else, even a thirteen amp charger could potentially push the total over 60.

I would doubt your friend is a usual electric car user.

He's not a usual car user and the car is a company car. It is just that about once a week he will have to visit a panicing client up to 150 miles away. The clients have fast chargers and he is able to charge to 80% there which is just enough to get him back to the office or home with a little to spare.
It is not as though he is doing this 5 days a week, as most clients are closer and some days he isn't called out. But it still means he needs that fast charger just so he can use the car in the evenings. You can't live a normal life if your Mother needs your presence and you say "Wait until tomorrow morning, because I have to charge the car, slowly in off peak hours".

One day he's going to have slightly less charge than he needs. Sounds like an electric car is not suitable for his work, or they need to get him the upgrade battery pack if that model supports one.

More likely, he pays attention to the amount of charge and will look for nearest fast charger on an app then charge for ten minutes to sort things out.

Things have moved on a lot. The network has closed a lot of the gaps. Far better in some places than others, but the gaps are less than the range of the vast majority of even half decent EVs.
1 - that depends if there's a coffee input & output session as well as just fuelling.
2 - not sure where you are getting your prices from. A new Nissan Leaf is about 28k, and there aren't many new ICE cars in the 7K price range, indeed for "Focus sized" cars they appear to in the 18k -25k range.

I've not done the sums recently, but with the current fuel prices the time to recoup the extra purchase price must have dropped somewhat (despite the price of electricity going up as well).

I guess there's more chargers where he is than here. Last time I looked at one of those apps, they're further apart than the average range of an electric car. Nice idea, not well thought out.

Round here, they have just opened up the Tesla chargers to others. More expensive than most but still a lot cheaper per mile than petrol. Dundee where my parents lived, there are more chargers than you can shake a stick at.

I've not done the sums recently, but with the current fuel prices the time to recoup the extra purchase price must have dropped somewhat (despite the price of electricity going up as well).

Especially as 90% of my charging would be from the roof.

The cheapest petrol car brand new is a Dacia Sandero for £6000.

Oh really???
Here's a link to Dacia's website:

https://www.dacia.co.uk/vehicles/sandero/prices-versions.html?gradeCode=ENS_MDL2P1SERIELIM2

In case you missed it the cheapest Dacia Sandero is £123595 (excluding all the get the car on the road costs).

As for your comparison with a £500 - You are not comparing like with like.

The cheapest electric car I can buy is £7000.

You really need to improve your searching.
A few seconds this morning on ebay and I found A couple in your price range (however they needed a bit of work to make them roadworthy, one at £1200 (tiny thing but possibly a real hoot to drive), a few strange (miss-placed) and then a one at 5k.
https://www.ebay.co.uk/b/Electricity-Cars/9801/bn_59498779?rt=nc&_sop=2

1.92KW on East facing side of roof gets feed in tariff even if we use it ourselves. West facing side 3.4KW was installed last year. Feed in tariff no longer available. It seems one can not get smart export guarantee and FITs at the same time. Also most of any excess is diverted into immersion heater for hot water. Even if I were able to sell it back to the grid,The best price currently on Smart export guarantee is 7.5p/KWH so even if we were getting paid, cost per mile would be pretty good even by ev standards.

Seems there's a Lada new for £9780.

It looks like vapourware just now, as Lada are only importing the Niva (4x4) to the UK, priced at about £24k.
Initial reviews indicate that your clapped out old Renault is a far better vehicle than that nice shiny new Lada Niva.

(But of course you might be able to snag one in the USSR Russia for a lot less, but then you will have to add on all the shipping costs, various taxes and duties that are imposed and a "Personal Import" IVA at about a £200 for a first time pass with zero advisories. Not forgetting that just now they are subject to sanctions preventing them arriving on our shores. If the IVA finds safety short-falls then you have to get all those sorted at your own expense within a defined time period before going back for a retest at about £40, fall outside that time and its full price again.)

What happened to the Lada Riva, a nice basic A to B car that was £4000 new in the 90s?

The 1990's one is no longer produced, and new car prices have more than doubled since then.
There's a new model available in USSR Russia, but it's not been type approved for use in the EU or UK due to "significant safety issues", so importing one to the UK would mean having to go through the pain of an IVA plus all modifications to bring it up to current UK standards before it could be used on the road over here. Then it would have to be taxed, but what road fund group does it live in? If there is no answer to that then it automagically ends up in the most expensive one, the first year that's currently £2365, subsequent years are about £170 (depending on how it's paid).
As for your Renault - why do you think I crossed out "Clapped out"? They are great until they die
Good luck finding an alternator that works for less than about £150. As for your door lock problem, sadly not uncommon, and it depends on what's filed, could be as little as a fiver, but could be several hundred pounds.

Finally the import duty rates haven't really changed for the last few years. Sanctions are entirely different matter, (and hopefully won't be around for too much longer), they prohibit the import of goods, and (currently) haven't affected the import duty rates. Current import rate from non-EU countries is 10% of the car price, then 20% VAT on the whole bill including shipping (£$%^&* VAT).