John Rumm wrote:

When you have a void under a join in the board, you end up with the full
weight of the person standing on it being supported on a third of the
thickness of the board (i.e. the bottom part of the groove, or the
tongue), so its quite easy to break something - especially as most are MDF
backed and that is quite weak in tension across its layers)

Which means presumably that a new board in the same position would sooner or
later go the same way.

I've been wondering about installing a new floor surface on top of the
laminate in the kitchen area (it's only a small corner section of an open
plan bungalow) - perhaps laminate again but with the planks running at
ninety degrees to the ones there now.

There are multiple snags though: the existing floor doesn't lay dead flat,
there would be two exposed edges ripe for tripping over and it would be
necessary to somehow fix down the new flooring so that it doesn't move. But
it should certainly solve the present problem.

And another thought that's just struck me: remove the existing laminate in
the kitchen and replace it with new flooring planks of the same thickness,
at ninety degrees. If I could arrange suitable junction strips of some sort
that might work, though I suspect that the different expansion tendencies
could well be a problem.