I just discovered my own answer...

I noticed that rows 6 and 7 were missing when I looked at the row headings.
That was a huge clue! First I tried "Unhide" but it didn't help. Then I
tried Data/Filter/show all. That did not help either. Last try was to apply
an auto filter and THEN "show all". That did the trick.

So...

It turns out I was wrong when I said I did not think the list was filtered.
It was not that obvious because show all command in the filter section did
not work in this case until I re-applied an auto filter.

No need for any further help. (But thanks anyway)

I will leave the test file up for a while in case anyone wants to take a look.

Quin