That didn't work, I still lose 6 hours on reboot because I set my timezone to GMT -6 Saskatchewan
It must be the mb-applet-clock that I downloaded from 3000Daniel
I'm just going back to GMT -0 London
EDIT:
it worked the second time. I had to set the zone and clock, reboot, then set the zone and clock again, and reboot again.
Now it's correct.