Channel 5 have updated the Demand 5 app for Windows RT and Windows 8. The Windows Store app has another update to stop the app crashing after 24 hours, this is the same issue as the previous update tried to address.
The app seems to work ok for me but still seems to have a couple of minutes of pre-roll video before you can actually watch the content. The app is free from the Windows Store
Release notes
This update provides a fix to the reported crashing issue after 24 hours.