Hi, HW.
I tried another experiment using my mobile phone (cell), with Android 10.
After logging on, I clicked on "JRA Magazine".
Ignore the index which pops up on the right with the "Box" index in it. Trying to download from there didn't work for me either.
Instead I clicked on the word "index" displayed below the "JRA Magazine" title.
This brought a full index of the newsletters and magazines with a clickable link for each issue.
Clicking on this link opened up the magazine and when that was fully opened in the magazine form, I could save the file as a PDF in the downloads section of my phone.
Again tried it twice and it worked perfectly both times. A little slow but no more than a minute. Depends on connection speed, I suppose.
At least you will be able to read about Alleda on your phone and while I haven't tried it, I'm pretty sure one can transfer PDF files from the phone to the laptop.
It might work for you, including on an Apple phone.