Tampered Event (external siren)

When adding a siren for the first time I have triggered the 'tampered' alert as a test. Now however I am unable to clear the event. I don't seem to be able to remove the 'Tampered' state. I have tried following help articles suggestions such as Reset and Remove (which seem unnecessarily complex) these result in the same thing as they involve removing the siren from the wallplate and thereby retrigger the tamper alert as the device is re-added. Am I missing something ? Didnt get much help from telephone support