Possible Clues:

• How fifty-one get run together indeed
• Indeed, just over fifty has been left out
• Did this get the eel shortened?
• The start of 7 down, indeed!
• The French turned, left out a vowel and died all twisted
• Skipped
• Indeed it was fifty-one that had a bit left out
• In short, one died in a mess at last
• Indeed, fifty-one may shortly be there
• Missed end of planned deadline -- a note omitted here