Somebody - PLEASE invent a tidy gene?

This time I have mislaid my car tax disc. It went from being put in an obvious place on the stairs where I could not fail to see it and display it on the car's windscreen, to POUFF!! Somewhere.

I have spent the whole morning looking for it, the plasterer came and went, the sun is going down, but the the bright blue circle is not showing its face.

Drat.