OK, this a big error.
I had my Z unplugged from the mains. I had logged out (I was aiming for suspend in the menu and missed) and then suspended it using the button.
It main the usual beep and went into suspend. I closed the clamshell and went to bed.
Next day, I turn it on. Log it in. It asks me for my timezone, welcomes me to GPE and everything is reset back to the defaults. Weird or what.