How can I get lost keynote presentations back onto my iPad,

Restore from a backup....if the presentation is not in the backup, you are out of luck.

Barry

Try this - Reset the iPad by holding down on the Sleep and Home buttons at the same time for about 10-15 seconds until the Apple Logo appears - ignore the red slider - let go of the buttons. (This is equivalent to rebooting your computer.) No data/files will be erased. http://support.apple.com/kb/ht1430http://support.apple.com/kb/ht1430

iPad Photo Recovery: How to Recover Deleted Photos

http://www.iskysoft.com/iphone-data-recovery-mac/ipad-photo-recovery.htmlhttp://www.iskysoft.com/iphone-data-recovery-mac/ipad-photo-recovery.html

How to Restore Lost or Deleted Files from iPad

http://www.iphone-ipad-recovery.com/recover-ipad-mini-files.htmlhttp://www.iphone-ipad-recovery.com/recover-ipad-mini-files.html

How to Recover Deleted Files from iPad

http://www.kvisoft.com/tutorials/recover-deleted-files-from-ipad.htmlhttp://www.kvisoft.com/tutorials/recover-deleted-files-from-ipad.html

 Cheers, Tom 😉

You can use a call MobiKin Doctor for iOS to get back lost data from ipad. Here you can recover various data from ios device. including SMS, contacts, call history, safari, notes, calendar, reminders, voice memos, photos, SMS attachments, etc. You can have a try. Hope this helps!