Originally Posted by Jono
Mount with CSK machine screws fitted with nylock nuts. This prevents undoing from outside only.
On mine you can't, as they are screwed into the wooden base of the seat cushion - so you can't get to the back of it.
On the engine box, they are mounted as you suggest, and as you say, impossible to get out when the lock jams (at least without damaging anything)...
As to where they should be mounted - I haven't really thought about it, that's were they were when it was built. They don't get that much loading, so I guess they they would hold the top shut wherever you put them, but you'd need to make sure that it was far enough away from the hinge that some thieving scumbag wouldn't be able to lever it off. It also helps that my jockey seats are straight sided, yours look like they are shaped at the top, which might make things more complicated.