Assuming they're wired devices, it still sounds like a programming issue.
It should work OTB, maybe if you can't find the attribute that's been changed start a fresh.
I would also start to consider if the detectors are in the best location.
One Way => The detection device blasts it's message out several times and hopes it is received by the panel.
Two Way => The detection device and the control panel can communicate and receive messages in both directions, acknowledging them.
I agree, this is a case that the ICO have been watching closely.
They are currently working with the MoJ on how this is to effect UK law, but no update has been given AFAIK.