Mav, thats one I havent heard - the lazer key thing - will tell Alan.
The last tank he bought had the same prob - but he phoned around first to find out costs for the replacement lock (not as expensive as he first thought) - and then drilled out the tumblers to get existing one out.
Khu - hope you get it sorted - try here???
http://www.studios92.com/guide/locksmith.htm