3x3 does not always make 9...

Met the charming David on a sunny Hackney street, with as joint goal to assist Mr M in replacing the battery for his smoke alarm.

Inside, the two alarms to be sorted were easily found, although taking them off the ceiling turned out to be a little more challenging... but GG'ers aren't easily defeated and we succeeded without breaking anything!

Unfortunately the batteries Mr M had at hand weren't the ones needed - AAA sized ones do not fit, it needs a 9V block. Mr M's friend popped out to get some, but could only find one. The smoke alarm in the hallway fixed, we made sure Mr M & friend knew how to replace the heat alarm (still working on old battery) and put it back on the ceiling, so fingers crossed the second stage of this mission gets fixed in the next couple of days.