Andy,
The only thing that lets the car down as a rep, is the exhaust. Cars of that age and type had a rear exit exhaust that turned downwards as it exited the rear bumper.
The mud flaps are moulded to the front wings and rear bumper, are these the type you have?
I personally woudn't put them on a road car as it means drilling the wings and bumper...
As is done on my rally car here...
Ian