On Friday, 3 January 2020 18:31:10 UTC, wrote:
My gas hob, on each burner, (as is usual) has a cast metal grid which
has four arms which finish just short of each of the burners. It works
fine with larger pans, but the smaller pans even on the smallest burner
tend to too easily miss the grid and tip over.

I'm wondering if anyone has found a solution? Might a sheet of
perforated metal, with large perforations, large enough to cover the
entire hob work?

Induction hob. Whilst said tongue in cheek, if you have some space, one of those single plate units is pretty inexpensive and would be an answer. (Provided your pans are suitable.)