I bought a Pi camera:
https://www.ebay.co.uk/itm/Raspberry-Pi-Wide-Angle-Camera-Module-Pi-Zero-Cable-Included/153078067107

However the standard Raspberry Pi camera mounts will not fit this, so I created my own. The camera module slides in and is a tight fit - but this means no screws/glue are needed.

For the bracket, I use the one from here:
https://www.thingiverse.com/thing:2886101

The camera stays in place because the two small screws on the back fit into the holes - its a tight fit to get them in there, but means it wont fall out.