P: Ability to download full resolution file from a shared folder

Yes it does Rikk.

The thing is, I am not the recipient of the Collection link.

Say my family want to download some photos to print off etc.

This of course may be by design. I imagine the majority of LR users may be professionals who do not want Clients who are recipients of links to have the ability to download Hi Res?

Did you try it when you were logged into your Adobe ID? The option for original appears there. 

Ah yes Rikk, you can already.

I allowed downloads, shared a link and copied it to another browser (that I wasn't logged in on).

Then I can download the whole Collection.

But, when you go to a single photo there is no option for original, only a low res. At least I think so.

Maybe I should have been more detailed on my original post.

Actually, just opened up the whole collection download in PS and they only appear under 500kb and 2048px width @14451451. Although in image size is says 7.97M etc.

Something I am missing/don't understand?

A typical original would be 6000px @ 300dpi.

I think you can download originals via Lightroom for web already: https://helpx.adobe.com/lightroom/help/lightroom-web.html