Thanks, Lettie. I did all this, but as you said, I should have clicked Preview, first. The reason it didn't post correctly the first time, is because the URL had two addresses linked together. So I clicked Preview *immediately* after I'd submitted, thinking that I had caught it in time. I then removed the first part of the URL and entered it correctly, only to discover above it, that the other had completely posted, after all.
LESSON: Once you submit, that's it!