Alistair, on your fishbook post..

.I believe in many cases a new fused spur might not cut the mustard, more so if one`s home is on a split supply with a neighbour, in other words an electricity company`s main supply cable fed into one house and then looped through to the neighbour as in many semi detached situations.... Also ideally the main fuse would be ideally 100 amps, whereas many shared supplies may be fused at 60 amps..?
Shared supplies obviously cut down on cable and installation cost for electricity companies.
Also perhaps worth noting may be effective earthing, anti surge protection (lightning strikes and the likes) as well as the installation of a suitable circuit breaker rated for the likely duration of the LOAD, 32 amps max in the UK, which may be drawn for circa 7 hours or more.
There are specialist installers, and in the case of Tesla and perhaps others there is a list of local trained installers on their web site who seem likely to have attended a course on the specifics of installation prior to being "listed"..?
It is just possible that for some time prior to electrified milk delivery "floats" there were somewhat faster electric vehicles..?
https://youtu.be/CRwEXaHTwsY Addendum, apologies Alistair, I drifted into max current household charging whereas your spur suggestion may have been more related to 10 amp charging via a 13A outlet..