Hi Tim,
I have one of the Bullock ones (I was given one by the original importer many years ago). It's a brilliant thing. I always use it if I'm abroad in the mog. I don't bother here but I would if I was leaving the car somewhere I didn't like the look of.It lies under the seat when not in use. Peace of mind. Mind you, you have to kneel on the ground to lock/unlock it. The Loc king looks neater to me.
Modern handbrake tops don't seem to lock the handbrake when unscrewed like the old ones did.
All security helps if it's not silly - like those uncutable steel securing wire that people thread through their canvas/leather bag handles...ho ho ho indeed.
Nick