Hello. Is it just one wheel, or just the back ones both put on the wrong sides? I assume it's just the one.
Have you had this car for ages, or was the incorrectly fitted tyre put on since you bought the car? If its the latter, you should be able to get the tyre place to change it cos it's blatently their fault.
(Simon, when did you get your turbo-tractor remapped/chipped? 180-odd BHP is sweet.)