Re: legal target
Get real. Maybe 30% could charge one EV at home, perhaps only 10% could charge 2.
More than 50% of the UK live in a detached (25%) or semi-detached house (32%). Detached and semi-detached houses invariably have a private drive/off-road parking and could charge one or two EVs (grid connection notwithstanding - but the parking space is there. moreover, two-car households tend to see one car there most of the time whilst the other is used by a commuter - if the connection is that poor, one can charge in the day, the other at night).
26% live in terraces. These are a bit more gnarly - Of the 200+ terrace houses on my road, >70% have a drive at the front (converted front garden) or a garage/parking space down "the backs", where they could sensibly charge. The ones at the bottom of the road might struggle, but a trivial analysis would indicate that your "30%" figure is utter rollocks, just like 67% of all statistics.
Likewise, of the 14% who live in flats... well my wife's old flat, and the new-build flat a friend has just moved into both came with dedicated parking spaces - charging facilities could be fitted. This will not be universal of course, but again, "flat" does not necessarily imply "no parking", though the installation of charging points would involve the cooperation of the landlord/residents association.
London is different, but 85% of us don't live in London, and a non-trivial proportion of the 43% of Londoners who live in a flat/apartment don't own a car to begin with because they have sensible public transport, rendering the question moot.