One idea suggested to me that worked when I tried it is a bit like the mallet one above - if with a slightly higher risk!
Loosen but do not remove the normal bolts,
take the car for a gentle drive around the block,
tighten the normal bolts up - nice and tight,
Bang the sacrificial socket back over the locking bolt and try to remove again.
At a guess, the wheel rocks a bit compressing the conical face on the wheel where the bolt meets it so when you tighten up the other bolts you have hopefully broken any corrosion and loosened the bolt a bit.
At any case it worked on the two wheels I had to remove after the locking nut tool broke.
Mind you, drive with loose wheel bolts at your own risk!
Loosen but do not remove the normal bolts,
take the car for a gentle drive around the block,
tighten the normal bolts up - nice and tight,
Bang the sacrificial socket back over the locking bolt and try to remove again.
At a guess, the wheel rocks a bit compressing the conical face on the wheel where the bolt meets it so when you tighten up the other bolts you have hopefully broken any corrosion and loosened the bolt a bit.
At any case it worked on the two wheels I had to remove after the locking nut tool broke.
Mind you, drive with loose wheel bolts at your own risk!







....
...

) and then welded the socket on, came off in the end with some persuasion from mr impact and sir big hammer!