does anyone know if it is possible to download El Capitan directly, as opposed to going through the App Store? I'd like to be able to upgrade, but App Store is blocked on my machine.
Here is a link to download the latest updates manually from Apple.
Here is a torrent file to download
InstallESD.dmg, getting speeds of 1mbps+. OS X is free and open to public so this isn't illegal.
This file's SHA1 Checksum is
306a080c07e293b6765ba950bab213572704acec. Here is a list of official Apple checksums. So this is official and not been tampered with.
If you are a developer, or know one that will give you his credentials, you can download it from https://developer.apple.com/download
If your are trying to upgrade from OS X 10.7 on an old MacBook (like I am doing) to get El Capitan and then be able to upgrade to the latest macOS, you can also try to use Internet Recovery. Press and hold CommandOptionR during startup and you will enter Internet Recovery. Then you can install the latest macOS version (High Sierra, at the moment).