Do you have locking wheel nuts? If not, it could be difficult to prove where the wheel was swapped. The garage which did the brake pipes will have needed the wheel key to do the job.
Incidentally, is it the tyre or the whole wheel +tyre which has been changed? Being kind to the garage, they just MIGHT have accidentally swapped the wheels with those from another car they were working on when doing the job, assuming the brake pipe was on the suspect wheel. You could always go to the second garage and talk to them, although I don't think you'll have any joy.