after a reboot my mini mac seems to have lost pairing with both wireless keyboard and mouse. How do I go forward from here?
You need to go to System Preferences and then go to the Mouse and Keyboard panes. It should be pretty straightforward from here, just disconnect the keyboard and mouse and then reconnect them in their respective panes. I can't go into anymore detail, because I only have a MacBook, which doesn't use Bluetooth keyboard and mice.