It appears it's not "designed" for Windows 8/8.1 as when you go to the website to download it, the Download link only appears on a Windows 7 PC. I had to use my partner's laptop to grab the installer.
In Windows 8, I had to run the program in Windows 7 Compatibility Mode. It then worked fine.
Using this Compatibility Mode in Windows 8.1 isn't working. Neither is Vista/XP Compatibility Mode.
When I try to open it, the process runs (in Task Manager) then ends around two seconds later - nothing appears on screen.