A family of Microsoft word processing software products for creating web, email, and print documents.
Thank you everyone for your replies. I've managed to recover the original document from OneDrive by looking at the version history of the document. This is the information the OneDrive team emailed to me, just incase this happens to anyone else!
Go to the OneDrive website at onedrive.live.com then sign in with your account.
Select one document (you can only restore one document at a time) for which you want to restore an earlier version, and then at the top, select Version history.
(In Classic view, select the document, then at the top, select More > Version History.)
Do one of the following:
If you're signed in to OneDrive with a Microsoft account, the file opens in a viewer. Select the older version that you want to restore, and then click Restore.
If you're signed in to OneDrive, the Version History pane opens. Select the ellipses (...) next to the version of the document that you want to restore, and then click Restore.
In Classic view or earlier versions of SharePoint Server, in the Version History dialog box, select the arrow next to the version of the document that you want to restore, and then click Restore.
If you see a confirmation message, click OK.
The document version you selected becomes the current version. The previous current version becomes the previous version in the list.