First off, we tried the trick to download an 8.1 ISO, but it doesn't work for us, because all our W8 machines came with it preinstalled and apparently you need a retail (non-preinstalled) key for this to work. Also, I don't see why I should have to waste ten times the time and bandwidth to upgrade ten different machines; in addition, I'm partially responsible for some machines that, due to contractual restrictions, can never be allowed on the public Internet for any reason. (These contracts were written long before anyone ever heard of a VPN.) If we can't find a way to download these files without the having the downloading computer immediately proceed to install and then trash them, then these other machines will never get upgraded - in which case we might not bother to upgrade any of our machines, just to avoid even more OS inconsistency than we already have in our shop.
Does anybody have any suggestions on how we can proceed under these restrictions?