Got me beat on vagcat. I can find the wiring loom and the belts, but not the pretensioner listed separately. Lists it as a complete belt unit ie "1J3857705S JNZ" in black/red (anni) and even thats a left hand drive one.... soz

There's dozens of variants depending on the airbag configuration, so be careful which one you get to not compromise the safety features of the car.
Have the belts been fired in a collision then? Is it even available as a separate unit? Should the belts not be disposed of when the pretensioner has fired?
Whatever you do mind you observe the fitting procedure, unplug the battery (!) etc
