Dispatchers hours are heavily regulated like signallers, however they do a far more physically demanding job in all weathers facing no end of hassle from the punters. Couple that with some of the (former) management who insisted on them spending the bare 45 mins meal break and them being outside for the remainder, I would say they have it far, far, far worse than the bobby does in a modern box.
Generally, the 12 hour is the 'total max' shift for operational s/c staff, however general rostering for drivers/guards/dispatchers should be a maximum of say 9.30/10/10.30 - the 12 limit is considered the shift max for use in times of disruption or emergency. This was not a training issue, it was a fatigue issue - the underlying cause when a regulatory body started poking about was TPE trying to save cash and use the absolute minimum of staff and length of shift was directly blamed for the string of incidents.