a little SA information....
When driving a vehicle on SA roads, an ADR Approved restraint MUST be fitted and worn, unless the vehicle WAS NOT fitted with seat belts from factory (eg, most pre- 1969 vehicles).
You CAN wear a racing type harness ....and get this..... but you MUST wear the factory fitted seat belt ASWELL.
If a harness is to be the only form of belt worn, it must be fitted and located within ADR standards, and have an Engineering Certificate to prove its legality. And i'm pretty sure the rear seat MUST be removed, which
then requires the car to have
another certificate identifying it as a 2-SEATED-VEHICLE, which
then makes your car a sports car (higher registration costs)
But this wont stop the police from taking your car off the road, simply because they THINK its not legal.... even though you have the certificates to prove it....
Either way, i used harnesses on my first mini for a year without any problems
or certificates....