Fay, I figured out what was happening with the links. On various tablets, laptops and devices which I checked the link on it went to the default web address onedrive.live.com setting encouraging joining up to OneDrive to download the pdf document.
To circumvent this simply copy the link text or link address and paste into a new tab.
For example:
https://1drv.ms/b/s!AmCrvJcXI6M6gQNn9A3WzUmDI1OV
When copied and put in a new tab it becomes:
Most computers and devices would have no problem but a few random ones seemed to have a Microsoft Office OneDrive redirect to encourage joining up to their cloud for storage.