Steve, From my memory of testing the canopy jettison system, the Master s/w armed the system and Jettison s/w fired the canopy bolts. The operation of the rear hatch is a mirror of the canopy system.The operation of the control column explosive bolt was operated by a lever on the left hand consol. During my time on Canberras there was no initiation of the canopy or hatch systems by pulling the ejection seat handles. As stated in previous posts the jettison s/w was a guarded s/w in the control unit.
The tip tanks were also jettisoned by explosive bolts.