Copying a document on SharePoint Online with full version History

Hi

I am trying find a way via an  Nintex Workflow for Office 365: HTTP Web service call that cpies a document item to another library once it has been approved.  My client wants to separate the working drafts from the final published articles. Hence the source library is excluded from search and has restricted access. Now there are few posts that mention Author.dll but only when referring to SharePoint 2013. I thought I might try this against SharePoint online:

My url is :   

{Workflow Context:Current site URL}‌/_vti_bin/_vti_aut/author.dll

And my Request Body which I have built with Dictionary looks like this

My HTTP Web Request Action sits within an App Step as this i smeant to deal with permissions issues 

Unfortunately, I am only getting an HTTP Unauthorised response. 

Anybody else seen this or attempted to do it with SPD.