When studying for my RT I found CAP413 Supplement 3 very useful - mainly because it has audible examples of text-book exchanges between controllers and aircraft. But when Steve Wilson suggested I use it to brush up on my RT I found that the sound links no longer worked. So I got in touch with the CAA help desk and Kevin wrote back to say that there is a mismatch between the latest version of Adobe Acrobat and their file.
The solution is to download the file to your computer and run it from there (rather than watching it in your browser). When it opens in your browser it doesn't have an immediately apparent save button. But I discovered the solution to this by accident. At the top-right is a button "Exit"-Home. Click this and a menu appears along the top. Click on the Floppy, as usual, to save.
Many thanks to Kevin Crowley at the CAA