Dude, I would go to a scrap yard and get a decent condition one, then put it on, take a few very reliable trustworthy buddies, go to rondebosch, to your wifes offices and set up a few of the buddies around exits. Look out for premises CCTV, other employees, traffic cameras and car guards.
I would stake out till the chap who is doing this comes along, wait for him to take it, filming it with my cellphone camera, then catch him, load in boot and drive off.
Go to undisclosed location, pull out finger nails one at a time, then smash toe nails with a hammer, then whack kneecaps with baseball bat.
Then break elbows.
By now the chap will have fainted or pissed himself. If fainted, he will regain consciousness by the time the adrenalin has worn off, and the pain receptors start firing again.
You break fingers, gouge eyes, cut tongue off and pour boiling oil in ears. Drop the guy off at ER asap as blood loss from the tongue can be deadly.
Burn your clothes, the hammers, the pliers etc. What ever remains after burning should be mixed with some pool acid, then reburnt. What remains, the ashes can then be spread around an open veld area, not your yard.
The guy cant say to police what happened, no tongue.
HE cant legibly write who did it, broken fingers etc and the inability to see will make it impossible to write, and even so, if he were able to write this out, what proof would he have that it infact was you (provided you are an attention to detail kind of guy)?
The deafness comes in, where they speak to him to tell him your name or car colour, or numberplate and he shakes his head to say yes or no etc.
You dont want any blood spatter in your car, clothes, hair etc.
You would to scrub under his finger nails etc before pulling them out
Nice thick plastic inside the boot should cover you.
Zip ties to restrain work well, if you use more than one and dont buy the cheap chine ones.
Legs are zip tied individually, then together, hands are zip tied individually, then together behind back, then zip tie legs to hands, then zip tie neck, then connect them all behind back with zip ties.
If he starts Pulling his legs down, it will pull arms down (and cause strain at shoulder joints, too much leverage will dislocate shoulder and since the neck is zip tied as well,it will pull neck, too much force will strangle the guy.
The only trouble you are going to have, is that this isn't necessarily a one man job, and the guys who will crack under interrogation will be the guys you take with you.
So know them well, or don't use them.
Don't get guys off the street, they will sell you out and turn state witness.
I will not say what I do for a living, but with these kind of things, you go all in, or not at all.
alternatively, maybe just ask the guy when you catch him, why he does it?