Great invention - really enjoyed my tour as a fast-jet base OC Armament which in those days included responsibility for an Ejection Seat Bay doing 6-monthly maintenance. I was even able to view them being used successfully from my office window in the Phantom era when runway departures across the bondhu due to nose-wheel steering faults were a regular occurrence. No dissatisfied customers thankfully.
More videos available to view at the M-B site:
http://www.martin-baker.com/ejection-media#prettyPhoto
and on their You Tube channel:
http://www.youtube.com/user/martinbakeraircraft/videos