Project box for rotary LCD interface

This is a 3d printed project box for an I2C user interface called the BV4212 (http://www.pichips.co.uk/index.php/BV4212) It is used as a front end to Arduino, RPi or other microcontrollers.
The display is a 128x64 LCD with back light and the input is by a rotary controller that also has a push switch, there is also another button for use input.
The box snaps together without screws and is quite a reasonable fit. The holes are designed for M3 x 3mm screws but in current design the holes are sli