Solution to Automatic login in Mojave
I thought setting Users and Groups to Automatic login and in Power enabling Restart after power failure and in Security Privacy the disable automatic login is unticked, would ensure the Mac would start after a power failure.
To ensure the Mac will automatically login, Go to Security Privacy, unlock Security and Privacy, tick the disable login and then untick it.
You will be asked for the admin password. After entering the password, shutdown and restart. This should enable automatic login.