Band tool holder in renders

Added band tool holder in renders as it's an important step that is only in the text

Required slightly re-defining the band tool holder by subtracting from a smaller cube - previous version was big enough that the camera was inside the cube, causing the render to fail.

Technically rendered in the wrong colour, but makes the part stand out more. Happy to be overruled if accuracy is considered more important

Closes #304 (closed) and hopefully #124 (closed)