I am not 'hell bent' on discrediting anything that's out there. Unlike you who appears to take anything at face value when it confirms your own prejudices, I prefer to look at the facts and figures and their accuracy and then take a view. I love your phrase 'highly likely'. In your opinion.
The best researched report that I have found is the one done by Field Dynamics and featured in the RAC report. The other reports, like that .gov one, I have seen simply take a tiny sample and then multiply it up with a bit of statistic fiddling.
The FD report assesses every building in England by using the OS MasterMap Topography layer
View attachment 189067
Incidentally, anyone can dip into it by using the Magic.Defra website which is a brilliant research tool.
They took the average sized car, added room to open doors etc and came up with a requirement for a parking space of 3.8m x 5.4m. Their algorithms then scanned that OS data looking for properties with that size or more. Each property was then cross-referenced with anothee OS dataset - AddressBase which matches 29 million Royal Mail postal address to unique property reference numbers (UPRN). Somehow - it's not clear - they then excluded factories, public buildings etc and that then resulted in them working out how many 'potential ' parking spaces there were.
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Blue would be space for one vehicle. Pink for two. Further cross-referencing produced this interactive chart by local authority.
https://onstreetcharging.acceleratedinsightplatform.com/
And they arrived at a figure of 65%. Only it will be lower than because in that photo of the house I posted above, clearly that plot has no potential. There will be other reasons why a potential space can't be used...bus stops, street lighting etc ...and his is acknowledged in the RAC report,
So all we can say is that it will be less than 65% but by how much, no-one knows.
But one thing is for certain and that it is not '
most' properties have the potential for off-street parking.
As you say, this aspect of the topic has run its course.