Unfortunately my refix fix didn't work: even with all four feet now securely
in place and correctly bearing on the strain gauges I can't get a stable
reading from the scale: it flits about from figure to figure, though always
within a range of about half a stone up and down.

So perhaps the problem is electronic? Whether it is or not, I can't see any
way of correcting it, sadly.

Thanks to all for the thoughts and suggestions.