Once she finds that we can have protection without the tripping
then the next stage of detectors upstairs can be carried out.

The upstairs ones are more important anyway. They are closer to the
bedrooms, so will be heard at night. Smoke rises, so in a real fire, they
might even activate earlier than the downstairs ones, even in a downstairs
fire.

Christian.

P.S. the beeping of the hush feature must be the most annoying thing ever.
Why would I want a 3000dB beep every five seconds to remind me not to set
fire to myself, whilst the alarm is in hush mode? It just encourages people
to remove batteries instead.