Guests cannot reboot their own VM's

[Piers]

Sorry if I am missing something here but every time a guest reboots I 
have to use the web GUI to start the instance again.

The docs say that it HA is enabled that they will automatically reboot - 
but I cannot find a setting to make this available.

Is this something unique to my set up (standalone testing server 
[CentOS]) or is there a setting I need to address/apply?

Thank you!

P