And as long as you're down the rabbit hole, take a look at UK speed limits in relation to vans. Vans have a lower speed limit than cars, but "Car derived vans"

And as long as you're down the rabbit hole, take a look at UK speed limits in relation to vans. Vans have a lower speed limit than cars, but "Car derived vans" are still considered cars and vice versa. That gives you a strange situation where, if your vehicle is available in both a car and a van form factor, the speed limit applied to your vehicle is based not on weight, load capacity or number of passengers, but on which came first - if the car was first, the car speed limit applies to the van. If the van came first, the van speed limit applies to the car.