My mini in the 70s had off-cuts of carpet in the foot wells so the road couldn’t be seen through the floor. Did me well though for a few years, I used to drive up to Nottingham from Oxfordshire with a toddler and a baby in the pram-top on the back seat and the pram wheels sticking out of the drop down lid boot, no number plate visible. Wouldn’t get away with all that these days.