I occasionally want to install some of my games on older computers, but I can't do that now as the DX8 executable was removed in one of the two recent updates for the game. Please can we have an option to download the old 1.01 version again for legacy compatibility? I can't even find a torrent of the original version of the game, so asking here is my only option.

Your best bet would be to raise a ticket with support to ask for the older game version - they may be able to provide a private download.