On Sun, 02 Aug 2009 11:29:01 GMT, Rob wrote:

With access from the inside, and about a 3mm view of the 'bolt' between
the striking plate and the door, what's the best and least destructive
way of removing this (lost key) external door lock?

If you have any idea what the lock type, is a locksmith would probly use
something like this and drill a single hole.
http://theinstituteofcertifiedlocksm...emplatekit.htm
I suspect that few (current) locksmiths would spend too much time picking a
mortice lock - although the tools to do so are still available.
http://theinstituteofcertifiedlocksm...ls2in1pick.htm

--
Geo