Can I disable my camera on my iPhone 6 lock screen?

I've went on to settings and passcode and camera isn't on there to disable.

I've heard of a lot of people that were never sure whether the camera was OFF or not, so they made sure & covered-up the lens…

Sadly there isn't. The only way to do it is to turn restrictions on and disable the camera function completely. You'd then have to re-enable it every time you want to use the camera