I think the smoke mark (new) must be from fire officer Daire testing it!
It's "be quiet" feature never worked very well and the break in the face is because the "be quiet" part of the face was always too stiff to push though the switch did engage if it was hit VERY hard.
Nowadays smoke alarms (and CO alarms) seem to very alot in expense.
(Watch out for price hikes after fire/CO stories reported in media!)
And the design seems to have disimproved over last few years.
You can't get a "be quiet" (for a little while) feature any more?
Is this because of over regulation?
Or because it doesn't pay the alarm makers to put it in?
Without a "be quiet" our kitchen smoke alarm ends up disabled (battery out or covered) for a while when we do end up with smoke. And on occasion when we make a big mess in the kitchen with smoke the same has been done to the alarm in the landing.
We have a CO alarm in Daire and Kate's rooms.
We have a smoke alarm in stairs landing, in attic room and in kitchen.