i work at a tyre garage and we get this sort of thing all the time, all wee do is tap an 18mm or 19mm impact socket on with a hammer the use a breaker bar to undo them, we also have a special set of sockets that are reverse threaded on the inside and basically with the aid of an impact gun just screw over them and undo them. most tyre garages should be able to do it for a small fee(i think my place charges about £25)