EPiServer CMO does where it creates a thumbnail of the published version and Previously Published version you select. This page, http://demo.episerver.com/en/Prospect-Campaign/ has ID 472 and one version with ID 1511. http://demo.episerver.com/en/Prospect-Campaign/?id=472_1511.
From what I know, the ID to the page is the same no matter what version you use.There might be some workaround to this but you might have to check the database to get the right version IDs and that's not very user friendly.
The easiest way I'd do what you need is via code, by programming a little, to provide a simple interface to your compliance department so they don't need to enter CMS and login to see the versions of a certain page. If for example you have the ID of the page you want to see versions from (and that is easy to get) then you can use the PageVersion class to retrieve all versions and then list them as links. Check the SDK http://sdk.episerver.com/library/cms5/html/AllMembers_T_EPiServer_DataAbstraction_PageVersion.htm and this post http://labs.episerver.com/en/Blogs/Allan/Dates/111319/111320/Show-Published-Pages-Versions-in-a-Specific-Time-Span/ for more information.
Hope it helps,
Is there any way to link to a version of a page from outside of the editor i.e. without going into the version tab and selecting the version and preview.
We have a requirement from our compliance department that for signoff they can link back to previous versions by some form of an id