Nexus 7 - 2013 - missed 5.0 rollout? My nexus 7 was showing "update available" but after thinking "You know if it's crap I don't want to deal with it now" (and reading later that there were some problems) I left it, 2 weeks later (a week ago) it came back, and I ignored it. 

Now I want to start using Material Design, but the update has gone, have I missed my window? I doubt it but Google's update policy... 

Anyway, can I "force" an update?
You can direct download the latest factory image here for your device. As far as I know, you need to note several things before force push the update:


Power off your device.
Enter to recovery mode (Power + Volume up and down buttons simultaneously for a few seconds).
Locate the zipped file and extract it to update the version. (May take a while)
Reboot


A bit of warning: Doing this will erase your all of your data and apps. Be sure to backup your data before doing this.

I hope this helps you.