3 am. Woken by a loud "Beep!", one I recognise instantly "please no, please no" I recite, trying to get back to sleep. "Beep!" FFS, smoke alarm, low battery. I stumble from the bed onto the landing and stand in the dark trying to figure out which one is beeping. "Beep!" oh great, the sound comes from the one just above the stairwell. I reach up and can just hold it, but not open it. I turn on hall light and squint up at it and see some words about inserting screwdriver. Stumble downstairs, find a flat screwdriver and try and insert and dislodge. Does not budge. So i go into the office, drag out swivel chair, and am then balanced on chair at the top of the stairs, screwdriver in hand and in my mind the HSE Alarm is going off - this is dangerous, do not fuck up. Eventually i manage to dislodge it and slide it off, and safely step down. I peer at it and it's a wired in one, and so I wonder why it's beeping. At this point the one in the corner beeps, not the one in my hand I thought it was! I reach up, flick this one open, remove the battery, and go back to bed.