When I read "saloon car", I was thinking of a car with "suicide doors" like the old 1960's Lincoln Continental. For anyone who doesn't know, they had 4 doors... The front two opened like you would expect with the hinge in the front of the car. The rear doors were backwards, and had the hinge to the back of the car.

The way those cars were built, if you got into a collision, the doors get stuck shut. That is a Bad Thing(tm).

Anyway, that was the first thing that popped into my mind. Probably because I could easily picture the front driver side door and the rear passenger side door as being the same part.