70% of the UK currently have a garage or off-street parking. (80% for homeowners) Another 20% have 'adequate street parking'.
Citation ? Bluntly, those figures are not believable simply from observation of the many places I've been to.
Looking around places round here, there's a lot of terraced houses with no front garden = no off street parking. Where daughter no 2 lives, they are lucky if they can park close to their house, daughter no 1 has double yellow lines past the house.
In our street, perhaps 1/3 of the houses have some off-street parking - but that needs to be qualified as some of them have more cars than they have parking for. So "X% of houses have off-street parking" is a meaningless statistic without some measure of how many of those actually have off-street parking for all vehicles that might end up as EV.
And "adequate on street parking" also needs considerable qualification. If both street lamps in our street had charging points installed, it would still leave significant parts without charging.
So firstly I call BS on your numbers, and I call even smellier BS on how they actually relate to the practicality of running one or more EVs.