i believe thatcham approved alarms comes with certificates of fitting and testing ??
thing is, in my opinion, if you know how to wire up an alarm system properly, it can be just as good, in my show car, its all microscan, alarm, immob, internal and perimiter sensors, wired up in a 6 point system
probably cost the same as a thatcham as well but without the certifitcate... :embarassed: