Since I've started writing I've found that if you pay attention to reader feed back there is real gold, "in thar hills." In this case a kind reader pointed out the one time in ten thousand words that I used "then" instead of "them". It didn't make the story any less readable, but offended my sense of right (write?).
Being a lazy sort I and not remembering the sentence he pointed out, I just searched for "then" with the plan of correcting that single error.
What I found instead is that I've been using "then" too many times! I've corrected and reposted, while cleaning up other errors.
Buy paying attention to my readers, I have improved my craft slightly.
Thank you all