I'm more bothered about someone pinching the wheels for the tyres, than the scabby old alloys I have on mine.
The locking wheel nuts have a letter code associated with them. A main dealer can either look up your VIN and tell you the letter your key is, ( they can do this with the radio code too). You will just need to bring the V5 along as proof of ownership. No good of course, if it's not the original key, (or radio).
I think for the locking wheel key, they are supposed to have a set to determine the correct one.