Yep. Been there, done that, thanks to numpty tyre fitters who left the key on my boot lid and sent me on my way
Needed a replacement socket to do the last one but 2 old sockets beats some of the prices I was quoted to get them off.
Don't let a tyre outfit overtighten them either. Happened to me before as well. Thought wheel nuts were 'kin tight so I loosened one of the non-locking ones. Took 200ft.lb. Figured it must have siezed. Tightened to same position. 200 ft.lb.
Locking key was already fubar when I looked at it. Got one nut off before it stopped playing. Took to k**k f*t. in desperation, as they were closest and I had a puncture. Offered to try with breaker bar (already done that, thanks). Sorry, mate. Nothing we can do. Took to independant tryre fitter. Couple of minutes with a windy wrench and 2 more were off. Turn up compressor, try again, hit with sammy, try again. Heat with the oxy torch, more windy wrench and off it came. Total cost 10 quid
Kevin