The most reliable way to provide the Collaborate recordings to students who do not have access to the site the recording was made in is to use the Guest Link from the original lecture.
The first step is to turn on the Guest Link feature for the Collaborate recordings you want to make available.
To do this find the original recordings (be aware you may have to change the date range that's being displayed for them to appear in the list); hover over the recording name and click the little arrow that appears (chevron), then click Edit. On the screen that comes up, put a tick in the box that says "Enable Guest Link" then hit the Submit button. The guest link will appear at the top of the screen. You can either copy it now or come back later and hover over the title of the session you need, click the arrow , click "Guest Link" in the little pop up menu. The guest link will appear again at the top of the screen. Select the link and copy (Ctrl+C).
To make the guest link available, go to the site of the original recording, and find the recordings, (be aware you may have to change the date range that's being displayed for them to appear in the list). For each one in turn, hover over the recording link, click the little arrow that appears, then "Edit" in the window that pops up, tick the option to create a guest link, hit submit. The guest link will appear at the top of the page, copy it. (If you don't get it then or need it again, it's ok you can get it again by hovering, clicking the arrow and a new item called "Guest Link" will now be available in the little pop up menu, clicking that will provide it again.
Now that the links are available you need to get them into the "new" site.
Display the guest link, select it, then copy (Ctrl+C).
Go to the new site you want the students to be able to access the recordings from, navigate to where you want the link to appear. Then either create a web link item, or else create a "normal" content item, write some text, select it, then click the little button that looks like links in a chain, paste the Guest URL into the top field, change the setting that says open in this window to Open in new window. OK it. Submit the changes to the item.
The link will now work for this session and any future sessions you roll the site into.
Repeat for each recording as applicable.
Should you wish students to be able to access MP4 or MP3 versions of the recording you can do this by finding the relevant recordings, click on the word "convert" on the right hand side in the column/s to create MP3 &/or MP4 files as desired. This process takes some time to run usually twice the length of the recording), but you do not need to stay logged in or even have your computer turned on while it's happening, pressing the button kicks the process off on the server. Once the word 'converting' has been replace with a play button. These alternative formats will also be available via the guest link create by the process described above. Also, you can right click and download the MP3/MP4 file/s and re-upload them anywhere you wish.
The file sizes in mp4 are quite large, but they do have the advantage of working on mobile devices (ipad, tablet, smart phones).