Of course I tried every password I could think of (including the correct one), but nothing worked - so eventually I clicked 'Reset password', and when that had no effect, 'Resend activation email'.
I didn't receive any email after several days, so on the login page I clicked the link that generates an email to the administrator - for whom I wrote a suitably-pleading email.
Then, three days later, I had an email to say the address was rejected. I was starting to feel pretty rejected myself...
Today, just for kicks, I decided to try the original known-to-be-correct password again, and although the first time I saw the 'you have exceeded the maximum number of login attempts. You now have to enter...' message, I used the same password a second time when I entered the picture-text code, and it - worked!
So, when you see the message asking for entry of the picture-text code, that doesn't mean the password you just entered was wrong - note for future reference
In the meantime (and before all this happens again when the logging-in automatically stops, probably next week), I just wondered whether the password reset and activation email - and administrator email link - is functional?
Thanks,
Thanks again!