FireAngel Fire/Smoke Alarm

I was woken up this Sunday morning at 7.15 am by the high-pitched chirrup of the smoke-alarm: the sound it makes at 40 second intervals when its battery is low. I closed the door and burrowed beneath the duvet until 8.30 am when I was finally forced up.

The offending device was on the hall ceiling and I was up on a chair inspecting it. The round squawker had no instructions so I tried a rotary motion - maybe it unscrewed? No luck, so I recalled the smoke alarms in my mother's house, where you had to insert a screwdriver and depress a tab, then slide it off its ceiling-mounted seating.

There was indeed a small gap for a screwdriver.

Here's the result. You can now see that the device attaches to its mount via three flimsy tabs: my first guess was right - it's an unscrew action. My leveraging efforts had led to the three tabs breaking off (one is shown next to the screws).

I am furious about both the lack of instructions and the shoddy construction. We won't replace it, so if we burn to death, the world will know to blame you, FireAngel!

PS: My mother has had similar problems in the past. If someone can invent a smoke alarm where the batteries don't run out (solar power?) and it doesn't emit that hyper-irritating squeak, the world will surely beat a path to their door. I recall that my mother resorted to hitting the damned thing with a broom handle - which sort of works.