I'm looking to replace the broken slate of an old driveway with
some kind of reasonably decorative paving slabs. I'm warned that
a minimum thickness of about 45mm in cast concrete slabs is needed
for parking a car on, which seriously limits the possibilities.
Basically, only fairly boring slabs in one or two sizes come that
thick.

I see a lot of Indian sandstone advertised, at about the same price
as decent concrete. Thickness is 25-35mm, but in sandstone this is
said to be OK for the load. Can anyone confirm that? Has anyone
actually used this for a drive?