G'day Theo,
Your SME box can retrieve an atomic time automatically if you can find an NTP server. Just tick the :enable NTP service" box in the time and date section. Try to find one near you so that there is as little latency as possible. You might need to play around to find one that is always online - some of the university ones seem a bit flaky.
You could start with the one I use: ntp.mel.nml.csiro.au just to see if the thing works then find a server near home.
Cheers,
Andrew.