Interesting... Using a device for a few weeks now and today decided to setup a new device. Tap each device, the new one correctly identify account and then offer to start fresh or restore from backup. It shows three backups, all devices I used in the last month - but not the one I actually use every day.
How long usually Android take between backups? Is there any way to force a backup?
Another alternative is the device I am using every day actually has a fault and never did a backup in first place.