Shout out to the original designer.
Didn't want my fan to be mounted on top of the box so extended the design to allow it to be installed inside along with a buck converter, moved the fan across slightly so it would blow on the stepper drivers a little more. Used 3x30mm to attach to the original base. May want to extend the buck mounts slightly as had to use mega short 3mm with a couple of nuts to allow it to grip. I'm a novice to designing anything but thought i would share.
Printed at 0.2mm layer height with 40% infill and supports on.