Thanks for the info AEO, but I have a questions.

Does the quick release come undone during repeated braking or does the skewer actually deform/elongate, loosening the assembly ?

What I want to do is remove the 'quick-release' from the wheel skewer. I tried looking for the pentagon nut unit that I used on my previous bike but I can no longer find them. Just before I head off to a machine shop and had 'bolt on' skewers made, I found these quick release ones where the handle can be removed. These suited my purpose perfectly except for the coming loose part.

Thinking back, the penta-nut skewer is made of the same chrome plated steel that my current anti-theft unit has. If I had my machine shop had some made, they'll be mild steel with no additional hardening or plating (he doesn't have those facilities). But those 2 other options will have the skewer screwed down rather than relying on a cam lobe to keep things togehter. If the skewer actually deforms due to disc braking forces, then I'll be wasting my time.

Thanks for the input.