Saved by the toolbox.

Ms L explained the issue with her bed and provided me with the plastic "foot" that she wanted fitted to the base of the bed frame. I asked if there was also a screw with it, but she said that was it. It was clear that the foot was a perfect fit to support the part of her divan base that was currently being supported by a board and four newspapers (from 2015 as we discovered!). I explained that without a suitable length screw I wouldn't be able to permanently fix the foot in place and whilst I had tools, I hadn't come prepared with screws.

She pointed to a small toolbox in the corner of the room and asked if there was anything in there that might do the job. After a bit of a rummage, I found a couple of suitable looking candidates, and after removing the divan section from under the mattress, I was able to securely screw the replacement foot in place.

With everything back where it needed to be, and the bed level (and stable) once more, under instruction from Ms L I moved the now redundant board into her kitchen, and disposed of the vintage newspapers in her recycling bin. Hopefully Ms L will now get a decent night's sleep once again.