Locking wheel nuts!!!

My car has locking wheel nuts.  Years ago the naughty people used to go out jack up a car and steal the wheels.  So now we have "thief resistant" wheels (note I used the word resistant, not proof) This is achieved by fitting some of the wheel nuts with a special nut that needs a key nut to remove it.
The problem is that there's only about a dozen different keys, and you can buy them all online. And far more importantly the nuts are not made out of steel, oh no!, they are made out of a steel case with a ceramic core.  This means A it's easy enough to steal the buggers, and B the nut itself if fairly fragile...  Yes you know where this is going.
I had to have some new tyres last week, after changing one, the tyre fitter sheared the locking nut on the other wheel, which meant I couldn't replace that tyre, or worse change the wheel if I get a puncture.  To be fair he did warn me it might break but I needed the tyre changed so had no choice. We did try a few tricks but the nut is bloody welded on.
I'm guessing that when the mechanics put the wheels back on after the MOT some 18 stone bruiser with muscles like Arnie tightned it up with a five foot bar.
Information for mechanics:  Wheel nuts should be tightened to around 100nm (103 nm for my car) with a torque wrench.  Not tighened by Guy the bloody gorrilla with a length of scaffold pole over the wheel brace for leaverage. And for what it's worth, most air guns will over tighten the nuts.