So ages ago I bought another small torch device to keep in my pocket. It was bigger than the one I did use in the end but I was looking for it rather than buying more batteries. Couldn't find it. Neither could 3 or 4 MOS. None of us could find it.
But out "looking for it" technique must have been a bit wonky
Last night I looked in the same place as I had looked in many times, where many other chaps had looked too.
Found it