In message , writes
Simpler yes, but expensive. I've used some of these in our flat in
London because there are only three detectors there however it's too
expensive for our house where we will have seven or eight detectors.

A nice extra on the ones I fitted was a mute switch so that after one
had activated and so triggered the rest they could all be muted apart
from the first one. Although my house isn't that big, 4 bedrooms plus
self contained annexe it certainly speeds up finding the cause of the
alarm. As someone else commented I also fitted an emergency light to the
smoke detector circuit, this is by the CU and mute switch.
--
Bill