Lost lock bolt key

Hope someone can help me out - I've lost my wheel lock bolt key. BMW either wants the number on the tip of the key or the lock bolt itself in order to provide me with a replacement. I'm in Potchefstroom and the nearest dealer is in Klerksdorp, so I'm not too keen to drive there just to buy a new key.

This is a picture of the bolt:


A 14mm Allen key is too large to fit and a 12mm one too small. Can anyone with lock bolts like these check the number on the tip of the key and PM me, please?

Thanks!