Any suggested repairer locations for gear assembly unit in Sydney?

I have removed the gear assembly unit from a 1999 C180 W202. The car's reverse lights unfortunately were not working and despite checking everything, all signs point to a faulty reverse light switch. The bugger is in the gear assembly unit and quite a pain to dismantle as you can see in this 14 part YouTube post.

I have the replacement reverse light switch part and the unit removed from the car but need somewhere to take both for repair. Without this the car can't get registered!



Any suggestions for the greater Sydney area are greatly appreciated.

Thanks in advance.